Diigo is an online tool to collect and compile your research on the web. Let’s say you viist a webpage that you find interesting. Just as you would if you would print it on a paper, Diigo offers you to “write it on any webpage”, complete with highlights and sticky notes.

You can also collaborate as a group – great for research or web design.

There’s a demo you can try without registering and also a Flash demo.

There’s a toolbar to install for Firefox. Just go to the page and choose Diigo in the toolbar:

You can add sticky notes to the whole page and when you visit the page, you will see it has some sticky notes attached to it and when you move the mouse over it, it will show the notes:

If you highlight any text in on the webpage, it will be marked within Diigo and you can choose to add some sticky notes and it will be shown when you visit the page:

You can also choose to blog about what you just highligted or forward your findings via e-mail:

I think this tool can be very useful within some projects. And it’s (almost) uninstalled and for free!