In my personal opinion, Web 2.0 is the usability of the website, a clear and easy to use design which features good textures.It has to be simple, please not that i used the word simple and not minimalistic. The content needs to be focused, clean and using the minimal amount of features to deliver that content! How to make it simple? Remove unnecessary features but dont sacrifice design or effectiveness.A central layout, most "Web 2.0" designs position their website centrally and use fewer columns. An exception to this would be e-commerce websites such as Amazon or e-bay. Who effectively use multiple columns to communicate products to the end user. Many new websites have a sperate top section / header which is placed across the top of the page. Lots of designs focus on simple, clean main navigation bars which communicate the main sections to the user. Of course, there are many more Web 2.0 'trends' of which you can find yourself but to me these are the most noticable.Hope this helps and im wondering what everone else's views on this are!