Web 2.0

The differences between the two are presentation and visual aesthetics versus the display of just raw text. The site appears to be well designed with option to search but defaults to different categorization of the links than the html site. http://www.diigo.com/about advertises reasons to use the site such as improved research productivity
The html version does not offer options to filter by tags or by annotation, more conventional search means such as Ctrl + F may be required to search the page text.

There are advantages for both formats depending on user preference. The html version does not contain advertising, which may be a plus for people with deep-seeded hatred for these irrelevant links getting in the way. I would prefer the site due to the appearance and search options. If I was unable to find what I was looking for, or found that I could not navigate around the site in a manner to my liking, I could always revert to the html version and perform basic searches or scroll through the text.