Check out this article, a nice mix of styles and the typefaces used, it's great to see the styles and faces that influence them...

Deconstructing the typefaces used for popular Web 2.0 brand names.

The Logos of Web 2.0
http://www.fontshop.com/fontfeed/archiv … -logos.cfm

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.

You can see some of these striking commonalities in Ludwig Gatzke’s compilation of nearly 400 Web 2.0 logos. Read on for a breakdown of the fonts used in a few of our favorite brands.
http://flickr.com/photos/stabilo-boss/1 … 060779001/

Check out
The Softies
The Futurists
The Classics
New Classics

See also:
An annotated list of all the companies represented in Gatzke’s compilation.
http://www.diggwatchblog.com/web-20-logos-and-links/
Ben Hunt sums up “current web style”.
http://www.webdesignfromscratch.com/current-style.cfm
Christopher Fahey rounds up a list of other sites that categorize design style.
http://www.graphpaper.com/2006/02-22_ca … ign-styles
Web2.0 Logo catalogs the sites and hosts forum discussions for each.
http://www.web2logo.com/