A recent blog post by John Marlott at Jones Day brought to my attention a ruling from last fall by the Patent Trial and Appeal Board (PTAB) concerning the use of the Internet Archive Wayback Machine (IAWM) for patent prior art in the context of an inter partes review. While this use of IAWM is well-established, the ruling suggests that IAWM may not unto itself be sufficient to qualify as a "printed publication" for the purposes of establishing dated patent disclosures.

Specifically, the PTAB judge noted that the demonstrated historical public accessibility of a given web document, as substantiated by IAWM, only established that it was technically accessible; it didn't go to its "public accessibility" — i.e., its discoverability by, dissemination to, and/or circulation within the relevant community of practice. Here is the critical excerpt from the ruling, First Solar, Inc. v. Rovshan Sade, IPR2023-00827, Paper 13 at 18 (PTAB Nov. 16, 2023) :

While IAWM is no doubt essential to these kinds of investigations, it's not the only tool for web archaeology. Curious about this case specifically and the more general possibilities for discovering applicable historical web context for these kinds of cases, I decided to perform some additional exploration and document it here. For reference, the patent in question was filed on 6 July 2010.

This ended up being a long post. For convenience, I'm providing a table of contents below for folks interested in particular approaches. You can also jump ahead to the conclusion, for a summary of findings.

Let's start by reviewing the key historical web resources.

The main prior art of interest was an installation guide for a commercial solar tracker product, with model name AZ-125. The copy referenced by the petitioner was an IAWM capture dated 2 December 2005 from the website for the product family brand, Wattsun.

By extension, we might reasonably suppose that the contemporaneous discoverability of either the Wattsun home page or the AZ-125 product page, from which the installation guide was linked, would also be relevant.

Reviewing the 2 December 2005 capture of the Wattsun home page, it appears that Wattsun solar trackers were manufactured by a company called Array Technologies.

IAWM has few captures of the Array Technologies website prior to the patent filing date. A 15 February 2005 capture of the "About Us" webpage suggests that the domain belonged to another company at this time. A 7 August 2009 capture of the home page shows a parked domain, suggesting that the solar systems company didn't own the domain at this time, either.

Given that, let's proceed only with the three aforementioned web addresses:

• The AZ-125 installation guide, at: www.wattsun.com/PDF/Wattsun_AZ-125_Instructions.pdf ;
• The AZ-125 product webpage, at: wattsun.com/products/wattsun_trackers/AZ-125.html; and
• The Wattsun home page, at: www.wattsun.com.

Backlink analysis

Google date operators

• They're over-inclusive of search results, because the keyword matching takes place against the most current indexed version of the webpage, not the historical one. That is to say, if the matching keywords weren't present on the historical version of a webpage, then it's less likely that it would've been included in the search results then even though it is now.
• They're under-inclusive of search results, because some webpages that may have previously existed and been returned no longer exist and thus have been dropped from Google's search index.
• How Google performs relevance matching and results ranking changes constantly, so any given search result may or may not have been included at all, or been more or less prominent historically than it is now. On the other hand, if we are to assume that Google strives and generally succeeds at maintaining the quality of its search results over time, a plausibly high-ranking search result may be a relatively stronger indicator of that it also ranked highly historically.

• INSTALLATION GUIDE , with a Google-recorded date of 15 August 2005. This appears to be a copy of the aforementioned AZ-125 installation guide , though in this case hosted on another website, that of the Alternative Energy Store, an electrical and renewable energy-related equipment provider.
• wattsun solar trackers: suggested retail price and ordering guide , with a Google-recorded date of 1 May 2003. This appears to be a product information and marketing document for Wattsun solar trackers hosted by SolarRay, a Colorado-based solar energy systems provider.
• How Solar Cells Work , with a Google-recorded date of 21 February 2005. This appears to be a booklet covering various types of equipment, including Wattsun solar trackers, compiled by Fred C. Gilbert Co., a California-based provider of metering pumps and lubrication equipment.

• Wattsun AZ-225 Solar Tracker for 12 Kyocera 200 Modules, with a Google-recorded date of 17 July 2008. This appears to be a product page for the Wattsun AZ-225 from Infinigi, a vendor of electrical and renewable energy-related equipment.
• TRACKED VS FIXED: PV SYSTEM COST AND AC ... , with a Google-recorded date of 8 February 2008. This appears to be a comparative analysis of the cost characteristics and performance of fixed versus tracked solar panels for SolarYpsi, a community-based solar initiative in Michigan, which mentions the Wattsun AZ-225 as the tracked solution.
• Helping You Control Alternative Energy! Woll Solar System, with a Google-recorded date of 2 November 2008. This appears to be a showcase of a completed project involving Wattsun AZ-225s by Control Alt Energy, a Pennsylvania-based renewable energy systems provider.

• The last-modified HTTP header was 11 September 2018.
• Viewing the PDF document properties, we can observe that both the created and modified dates were meaningfully earlier — 18 September 2008 and 27 May 2015, respectively.
• The latest IAWM capture of one of the web addresses cited in the document that resolves to an actual webpage (i.e., as opposed to a missing page) is 11 February 2009, corroborating that at least some of the document content originated from prior to the patent filing date.
• However, the earliest IAWM capture of any content from the parent SolarYpsi website is 27 June 2010, and no link to the document was readily apparent browsing around the oldest captures.
• Also the domain itself was registered on 2 July 2009.

• Active Trackers Items at ALTERNATIVE ENERGY STORE
• Active Trackers - DIY Solar Panels & Renewable Energy @ AltE Store

• A copy of the AZ-125 installation guide separately made available by a commercial provider and
• Information about and marketing of Wattsun solar trackers, including the AZ-125, by at least four commercial providers.

YouTube date operators

• Wattsun Solar Tracker, a time lapse of a Wattsun solar tracker following the sun, published on 8 June 2007.
• Six Wattsun Solar Trackers, another time lapse of a group of Wattsun solar trackers following the sun, published on 18 April 2008.
• Wattsun solar tracker time lapse, another time lapse of a Wattsun solar tracker following the sun, published on 10 August 2008.
• Wattsun Solar Trackers, another time lapse of Wattsun solar trackers following the sun, published on 15 February 2008.
• Solar Tracking array installation, a time lapse of the installation of a Wattsun solar tracker by Blue Sky Power, a solar systems provider based in the UK, published on 11 May 2009.
• Visite de l'usine CNPV à Dongying par Wattsun, a slideshow of a visit by Wattsun representatives(?) to a factory in China, published on 4 June 2010.
• PV Solar Tracker Location Time Laps shadow study, a time lapse shadow study to prospect the siting of a Wattsun solar tracker, published on 10 June 2008.

• The search result with title, Wattsun Solar Tracker (published on 8 June 2007) had ~73,000 views as of 5 January 2014. While this is more than three years after the patent filing date, we can observe that the video has only gained ~3,000 views in the last decade, suggesting that the views are heavily weighted towards the first seven years after its publication.
• The search result with title, Wattsun solar tracker time lapse (published on 10 August 2008) had ~5,000 views as of 21 April 2012. While this is almost two years after the patent filing date, we can observe that the video has only gained ~2,000 views in the last dozen years, again suggesting that the views are heavily weighted towards the first four years after its publication.

Bing date filters

• 2008-2009 Colorado Solar Energy Catalog by CSolarEnergy - Issuu, with a Bing-recorded date of 31 July 2008. This appears to be a product catalog uploaded to a document-hosting website by Colorado Solar Energy, a Colorado-based solar energy systems provider. Access to the publication itself is limited, but the search result snippet suggests that the catalog contains an entry for the Wattsun AZ-125 solar tracker.

• Wattsun solar tracker time lapse, with a Bing-recorded date of 10 August 2008. This is among the previously reviewed videos discovered via the YouTube date operator-enabled search.
• Wattsun Dual Axis Trackers reviews altE, with a Bing-recorded date of 22 June 2008. These appear to be reviews of Wattsun dual-axis solar trackers on the previously observed Alternative Energy Store.
• WattSun Tracker : All Things Hardware For Solar Installations, with a Bing-recorded date of 4 September 2007. These appear to be posts discussing Wattsun solar trackers on Solar Guppy, a forum dedicated to solar technology and products.
• Wattsun Solar Tracker, with a Bing-recorded date of 8 June 2007. This is among the previously reviewed videos discovered via the YouTube date operator-enabled search.
• FLEXmax 80 and Wattsun AZ-225 DA Tracker install problems, with a Bing-recorded date of 13 September 2008. This appears to be a post discussing the setup of a Wattsun AZ-225 on a forum for OutBack Power Technologies, a power conversion solutions provider.
• Review of Wattsun Dual Axis Trackers at altE, with a Bing-recorded date of 30 June 2010. This appears to be a different web address for the same review of Wattsun dual-axis solar trackers on the previously observed Alternative Energy Store.
• Tracking Systems Evaluation for the "Hybrid Lighting System", with a Bing-recorded date of 5 January 2009. This appears to be a paper mentioning a Wattsun solar tracker from the American Society of Mechanical Engineers 2003 International Solar Energy Conference.
• Solar Energy Finds New Home at T.S Designs | GreenBiz, with a Bing-recorded date of 9 October 2003. This appears to be a story in GreenBiz, a green industry trade publication, about a company setting up a large solar tracking array.
• Countryside's off-grid system installation. - Free Online Library, with a Bing-recorded date of 1 November 2006. This appears to be an article detailing the setup of an off-grid electrical system including a Wattsun solar tracker for Countryside, a publisher of farm-related periodicals.

• Two consumer reviews of Wattsun solar trackers;
• Another commercial solar energy systems provider working with Wattsun solar trackers, including the AZ-125;
• Two (previously noted) videos about Wattsun solar trackers;
• Two posts about Wattsun solar trackers on related forums;
• A solar energy conference paper mentioning a Wattsun solar tracker; and
• Two articles about companies setting up Wattsun solar trackers as part of larger solar energy equipment deployments.

X date operators

• An account for the Advanced Energy conference advertised that a representative for Wattsun would be presenting on solar trackers at the meeting. Notwithstanding the X user profile indicating that it was for the 2010 conference, the shortened link resolves to the (now defunct) program for the 2009 conference; the profile must have been updated subsequent to when the tweet was published. In any case, if we check out the 2009 conference website in IAWM, we see their claim that the 2008 conference had nearly 1,000 attendees. Looking at the program , we also see the aforementioned representative from Array Technologies (i.e., manufacturer of the Wattsun product line) on the agenda.
• An account for a green energy solutions provider, Clear Blue Energy, reported that they were designing a system for a customer incorporating a Wattsun solar tracker.

Reddit threads

Conclusion

• A copy of the AZ-125 installation guide , separately hosted and made available by the Alternative Energy Store;
• Information about or marketing of Wattsun solar trackers by seven commercial providers: Alternative Energy Store, Clear Blue Energy, Colorado Solar Energy, Control Alt Energy, Fred C. Gilbert Co., and Infinigi, at least five of which reference the AZ-125 solar tracker, specifically;
• A conference paper from the American Society of Mechanical Engineers 2003 International Solar Energy Conference and a Wattsun representative presenting at the 2009 Advanced Energy conference;
• Seven videos, two of which plausibly had thousands of views by the time of the patent filing date;
• Two articles about companies setting up Wattsun solar trackers as part of larger solar energy equipment deployments; and
• Two posts about Wattsun solar trackers on related forums.