PubSub is an Internet search engine for searching blogs.
The site operates 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 is found, the user is notified, even if it occurs months after the initial search. This feature has led PubSub to call itself a matching engine.
Results can be read on the service's website or on an optional sidebar, available for both Internet Explorer and Mozilla Firefox.
PubSub is currently in something of a problem as noted in //bobwyman.pubsub.com/main/2006/06/the_rumors_of_o.html this blog entry by Bob Wyman.
Our days are numbered. A recent attempt to execute a merger has been blocked and we've been blocked from raising equity financing that would allow us to continue to pay salaries and pay off our $3 million in debt. Thus, our "doors" will close soon if we can't find someone to pull us out of the current situation. Persons with fast access to cash and a desire for some of the industry's best technology are advised to contact us rapidly...