One of the original popular search engines on the Web. It was one of the first indexes of World Wide Web pages by title and URL.
It's got a funny history: as far as we know, AOL took it over and they tried to protect the word "crawler" as a trademark for a technology that is similar to another technology called "spider" which many search engines use. Then, Excite got WebCrawler, and now @Home owns them. Webcrawler was defunct for quite some time but now it looks like it's back up - what nostalgia!