I am really happy to hear that there has been a drastic improvement in terms of memory usage. At one point of time I could easily relate Firefox as one of the most memory leaking application I came across. But then there was other cousin of firefox, flock that had the same issue. Most of the improvement in beta 4 over beta 3 are based on community feedback. We should be seeing community development and support as the next generation development platform. As a sneak peak check out the address bar.

Zotero is an extension which is extensively used by researchers around the world. What it can do is take information accumlation and storage to next level. From managing your citations to bibliograpy, it easily beats out most of the proprietary softwares like end note. Being a community driven project it enjoys great support. All the features of Web 2.0 like tags and snapshots are integrated in this extension. Personally this happens to be one of my favourite extensions.