Lloyd Sakazaki has written a good overview of recent trends in global websites. It is based on Alexa data, a stats source which comes under regular fire for its faults (most recently ex-Netscape boss Jason Calacanis took aim). Nevertheless, there are some interesting underlying trends in the Seeking Alpha article. Not new trends, but well stated.
Over a two year period (Nov 2004 - Nov 2006), there have been 5 new websites enter the top 15 of Alexa in reach - myspace.com, live.com, youtube.com, orkut.com, wikipedia.org. Two of those are now owned by Google, which of course has shown significant growth of its own accord over the past two years.
The overall trend is that user-generated content is the defining feature of all of the new top 15 sites - except maybe live.com, which is basically just a replacement (sometimes a duplicate) of other microsoft properties in Alexa. So whether you call this current era of the Web the Read/Write Web, or Web 2.0, or whatever - the proof of how it is different is right there in those alexa stats. Also as Sakazaki nicely points out, the success of search in this era is derived from the growth in user-generated content - since there is so much content nowadays.
Incidentally, behind the tired and tabloid-level communism references in this Register piece - lies a good point. Is Ajax a strong enough technology to take us to the next era of the Web? Perhaps not. But I agree with Ryan Stewart's assessment that, for all its faults, "Ajax has done a lot to raise the expectations of end users and gotten developers to think differently". Also I'd add, as the Google Docs & Spreadsheets developers suggested recently, that Ajax is still the most 'web native' way to develop interactive web apps. Although having said that, I don't believe myspace, youtube, wikipedia or orkut rely to any great extent on Ajax? So it's not like this era of the Web is dependent on Ajax. It's an enabling technology, but not the essence of the Web circa 2006.
Anyway, back to the high level trends. Seeking Alpha also notes that many of the fastest-growing websites are localized Google properties - showing two clear trends, the importance of Google and the internationalization of the Web. The former gets plenty of press and blog coverage, the latter less so. But both are of equal importance in my view.