Sorry if this was posted before but I didn't see any hint that it was.
Anyways, it's still no longer my main annotation tool after mwang alerted me to Scrapbook+ but nevertheless:
http://blog.diigo.co...iigo-v4-is-live-now/The improvements seem minor (compared to the level of improvements expected of Diigo), but the aesthetics of the interface feels comfortable again. (If you weren't a fan of v3 and felt it was too confusing.)
Downside is the forum/group seems much harder to differentiate between bookmarks and posts (but I'm not seeing many complaints in their forum so it's probably tolerable) but the upside is that the toolbar now has a button where you can hide the toolbar and that the highlights are much easier to read again because they aren't black texts on white backgrounds with a thin layer of line to denote a box... but instead are actual snippets of gray background.
Main noticeable feature is the highlight pen which is a menu that pops up in a highlight so you could easily switch colors, add inline sticky notes and delete the highlight without clicking on a drop down arrow but just hovering your mouse over it.