I’d like to hear about any thoughts on Web 2.0 technologies with regards to SEO?
“Web 2.0” is a fairly meaningless buzzphrase, that people use to refer to myriad different features of websites, from user-interaction to shiny-effect background fades.
In terms of SEO, it doesn’t make any difference, per se. If it improves the quality of your content, that’s good. If it improves the number and quality of your backlinks, that’s good. If it fills up your pages with meaningless cruft, that’s bad. If it means your site relies on Javascript to work properly, that’s bad. If it has no real effect on any of those, it won’t have any real effect…
My thoughts are that using one of those terms is bad enough, but using both of them in the same sentence makes me want to bang my head against a wall 
The term Web 2.0 is commonly associated with web applications that facilitate interactive information sharing, interoperability, user-centered design,[1] and collaboration on the World Wide Web. A Web 2.0 site gives its users the free choice to interact or collaborate with each other in a social media dialogue as creators (prosumer) of user-generated content in a virtual community, in contrast to websites where users (consumer) are limited to the passive viewing of content that was created for them. Examples of Web 2.0 include social-networking sites, blogs, wikis, video-sharing sites, hosted services, web applications, mashups and folksonomies.
The term is closely associated with Tim O’Reilly because of the O’Reilly Media Web 2.0 conference in 2004.[2][3] Although the term suggests a new version of the World Wide Web, it does not refer to an update to any technical specifications, but rather to cumulative changes in the ways software developers and end-users use the Web. Whether Web 2.0 is qualitatively different from prior web technologies has been challenged by World Wide Web inventor Tim Berners-Lee, who called the term a “piece of jargon”[4] — precisely because he intended the Web in his vision as “a collaborative medium, a place where we [could] all meet and read and write”. He called it the ‘Read/Write Web’