2.1 Technical Issues
Web 2.0 is attached to a number of technologies that were around before the term was used ("Why Web2.0 Matters:", 2005). There are a range of technologies that aim to use the internet as a platform and to develop desktop application-like experience over the internet.
With the growing demand for more interactive sites increasing levels of multimedia causes issues for accessibility. Sites incorporating video, audio and other platforms such as Flash and client side Script rich web pages are leaving behind those who cannot access the technology. There are other technical issues with Web 2.0 when user generated content is dynamically added to a site especially when any styling is attached to the content.
However I am going to focus on AJAX as it is a common tool that developers use to implement Web 2.0 sites.