IAwiki is a collaborative knowledge base for the topic of InformationArchitecture. Anyone can contribute, and there are no pre-registration hoops to jump thru ... just click the "Edit This Page" link at the bottom of any page.
As with Firefox, you can add new features and extend OpenOffice.org's functionality by installing extensions. Here some of the most useful ones to try.
1001 is a desktop client to be used in conjunction with Flickr, 1001 not only uploads photos to your Flickr account, it notifies you anytime new photos from contacts, tags, anyone, everyone are uploaded.
Jajah Phone Buddy is a little software application that touts itself as being able to add "automatic telephone dialing to almost any [Windows] application" via Jajah's VoIP software. Jajah, a recent competitor to Skype, already has a plugin for Microso
WebSnapr lets you capture screenshots of (almost) any web page. Let your visitors to instantly visualize any web page before clicking. Increase site traffic, click-through rate and site stickiness.