SimplePie: do stuff with RSS feeds
SimplePie is a PHP class which makes it easy to grab and use the RSS feed from services like Delicious, Flickr or Twitter. So you could take the feed of results of pages mentioning your product of brand from Google Blogsearch, and make them appear on your blog sidebar.
Of course, there are other ways of doing this: for simple feeds, there may be widgets that do it more easily. And PHP5’s SimpleXML functions are pretty good. But SimplePie can handle a bigger range of feeds, more intelligently and enable you to do clever stuff like filtering without getting too bogged down in the XML itself.
See it in action (powering the search results from Hansard and Delicious links) at: http://interactive.dius.gov.uk/scienceandsociety/site/debate/
