PubSub was a prospective search engine for searching blogs, press releases, Usenet, USGS earthquake alerts, SEC filings and FAA Flight Delay information.The site, founded in 2002 by Bob Wyman and Salim Ismail, operated by storing a user's search term, making it a subscription, and checking it against posts on blogs which ping the search engine. When a new match was found, the user was notified, even if it occurred months after the initial search.