I love wikipedia, the online encyclopedia whose content is created by anyone and everyone on the web – but over the past few years, it has come under fire.  Problems like hoax pages and manipulation of entries for political ends have plagued it.  However, arstechnica has a nice review of the recent accuracy comparison of wikipedia to Britannica

The exercise revealed numerous errors in both encyclopedias, but among 42 entries tested, the difference in accuracy was not particularly great: the average science entry in Wikipedia contained around four inaccuracies; Britannica’s, about three.

Britannica, however, disputes the study’s findings.

Do you have any other favorite wikis?  The only other one I use on occasion is Theopedia (but I see that they have "exceeded their bandwidth" – I guess they’ve gotten too popular.  They better up their bandwidth purchase.