Ok, after few days I can say that I find it EXTREMELY useful. The tagging feature is great for having everything neatly organized, and I'm already full of great reference materials for pretty much anything I'd like to write about on blog, Twitter, forums, Stack Overflow, etc. :)

As for more suggestions, a pretty obvious one is a browser plugin. While bookmarklet is nice, a plugin would likely allow to offer more features (like list of recently added links as popup menu, search mechanism, etc.). I guess it's not hard to turn bookmarklet into Chrome plugin, but please don't forget about Firefox users too :)

Some kind of support for mobile devices (similar to ReadItLater plugin for Dolphin Browser) would be great. Less so for phones - since it's not a "save for later" utensil - but more for tablets.