Just discovered Wikalong. You can use it to make notes on various web pages you visit and make some notes.
Wikalong is a Firefox Extension that embeds a wiki in the Sidebar of your browser, which corresponds to the current page you are viewing.
In its simplest form, a wiki-margin for the internet, but it can be much more.
Wikalong can be used as a roaming blog. You visit a web page and instantly view what others are saying about this. You can edit the comments (wiki style). I love this stuff.