Analysis of Web 2.0 Logos over at Fontshop. There are the Softies, the Futurists, the Classics and the New Classics.
There is no official standard for what makes something “Web 2.0”, but there certainly are a few tell-tale signs. These new sites usually feature modern web technologies like Ajax and often have something to do with building online communities. But even more characteristic among these brands is their appearance. Web 2.0 sites nearly always feel open and friendly and often use small chunks of large type. The colors are bright and cheery — lots of blue, orange, and what we jokingly call the Official Color of Web 2.0: lime green.
More about current style in web design:
More Web 2.0 logos
Current style in web design
Netdiver Best of the Year 2005
The International Compliant Style
Categorizing Design Styles (from here I had a lot of the other links)