I just looked at the new research megatool Diigo and though several bloggers have covered it in the past and in previous incarnations (including our charming leader) I think they really missed the boat when many called it an unexciting entry into the crowded social bookmarking space. This is a web based knowledge worker's dream come true, it's the kind of thing that makes me love web apps.
The Reno, Nevada based company's name is an acronym for "Digest of Internet Information, Groups and Other stuff." It does offer a browser bookmarklet, but you'll want to grab the Firefox or IE toolbar to use the best Diigo has to offer.
In addition to nailing the basics in social bookmarking, there are many features here that give this system huge value whether or not it ever builds a network effect from a large number of users.
search for your highlighted terms in seven different verticals from local to TV to stocks.
These search functions are all rearrangable by drag and drop from an admin page and it's not nearly as complicated to use as it might sound. This drop down menu is also one of many places you can take highlighted text directly to a blog post in a number of hosted blogging platforms with APIs.
In case you haven't already gone to the Diigo site and started using the system based solely on the above, here's some more.
The social bookmarking function is very nice. Easy public/private designation with the default being your choice. Cached copies of every page you bookmark, a feature that has proven invaluable to me several times in the otherwise unusable Furl.net.
The site is largely about annotation, though. I can tell the Diigo toolbar to show me whenever a page I'm on has had notes left by myself or other users, whichever I prefer. I can leave stickynotes, private pop-up annotation, attached to any highlighted text and those notes will remain available whenever I return to the page later. I can also email a copy of any page, marked up with my notes, to people who are not Diigo users and they will still be able to see my annotation. Very cool.
Bookmark simultaneously in other social bookmarking systems, find my search terms on a page and highlight them different colors, search my or everyone's archives by title, URL, notes or full text. This service is amazing! So many times I've used a "Technorati This" bookmarklet or a "del.icio.us look up" bookmarklet to do just two of the numerous things that Diigo does with a single click.
I am very impressed and would feel ridiculous if I removed this toolbar from my browser and went back to performing any of these functions manually. There would have to be something terribly wrong that I'm not seeing yet. You can call me on it in a month, I'll bet I'm still using this. Using Diggo doesn't even mean abandoning Del.icio.us – it's easy to use both at once and gain all the functionality of Diigo.
Ok, enough gushing – what improvements would be good to see? More date stamping, I can see who has bookmarked a page but it's not easy to see when. Dedicated notes pages unattached to any particular URL I'm bookmarking, just to add to my archives on a given topic. The ability submit notes and images by phone. Both notes pages and phone submission are possible with the open source tool Markaboo. Recommended users, there's no reason not to offer me users, URLs and tags that overlap with my own archives.
All in all, this is an awesome tool that must have taken loads of work to put together. I wish this company a lot of luck, I think they have made a very cool product.