We Feel Fine | I quite like this tool as it allows you to observe (and quantify to some extent) feelings amongst the blogger community. It works by trawling new posts on MySpace, Blogger, LiveJournal etc etc, and looking for posts that mention feelings.
For example, if I write, “I feel good” (which I do seeing as you ask…), that gets counted and added to a database. In addition it will also tag what info it can find from your profile (eg country, city, age, gender etc). The feeling is then compared to a list of 5,000 (drawn up by hand) and recognised feelings will be displayed on the site. You can view feelings as a kind of buzzing horde, or ordered into metrics and you can filter by age, gender, location (even the weather at the time of posting). The visualisation is very nice too especially the weather view! Give it a go..