The Internet Archive has had a Wayback Machine for quite some time. The Wayback Machine is a portal to archived web sites, collated from continual periodic spider crawls that can (as in "put into a can") web sites at various points in time. From a patent prior art standpoint, the Wayback Machine is quite limited, but noteworthy. Google has a cache mechanism that is patchy, so even less useful.

Going "wayback" on the web has been mostly useful for Internet domain disputes and other intellectual property issues, and as well, in a few instances, criminal trials, but will increasingly be a significant resource for prior art searchers. For now at least, the best product prior art search mechanism for software and computer-related products continues to be Thomson-Gale InfoTrac.