The good:
Diigo imports bookmarks from elsewhere; tags pages by topic; lets you mark up and share Web pages; has a simple interface; toolbar and bookmarklet allow quick bookmarking; bookmarks simultaneously to rival services; searches text and comments within bookmarks.
The bad:
Diigo's subscription features are under construction; doesn't automatically merge similar tags; doesn't preview bookmarked pages.
The bottom line:
Diigo lets you save, import, tag, highlight, mark up and share Web pages--offering more advanced research tools than Del.icio.us.
