Reggie Freeman wrote in his blog http://reggiefreeman.blogspot.com/2006/02/social-bookmarking-and-annotation.html:

“Diigo is still in its beta stage, but looks to me to be one of the most comprehensive social bookmarking and annotation tools on the web. To use all of the features, one must install a toolbar to their firefox browser. I’m not crazy about having another toolbar to take up my viewing space, but given the features it has to offer, I’m willing to make the compromise.”

First, thanks, Reggie, for a nice write up on Diigo. Reggie’s comment bring up a question that users asked frequently – why a toolbar?

Indeed early on we faced the dilemma of deciding what would be the best way to offer all the features we envision Diigo to provide. Although we understand and appreciate that some users may be reluctant to install another toolbar, after considerable evaluation, we still went ahead with the toolbar development because we feel it’ll offer the most versatile platform to give users all the bells and whistles we plan to offer. Of course, we’ve also made a conscious design to allow it to be customizable so that a user can decide to keep only the component(s) he wishes. We know how precious your desktop real estate is!

Other enhancements will be also forthcoming that won’t require a Diigo toolbar installation. However, to fully experience all the bells and whistles that Diigo offers, we still highly recommend our toolbar!