Performance may vary

A new study by WatchMouse finds that Facebook is slow and unresponsive compared with many other major sites.

WatchMouse monitored 104 sites and placed Facebook at the bottom of the list because of slow loading times and frequent errors.

WatchMouse measured the sites' performance using its Site Performance Index, which "quantifies the user perception of speed and availability of a site in a single number."

A score of 500 signifies good performance, and 1,500 or higher bad performance. Facebook scored a 6,629, though WatchMouse did not detail the reasons.

Mashable speculates it's a result of the many third-party applications. But if that were the case, performance would vary from user to user, depending on how many apps were added.

Though WatchMouse calls Facebook a bad performer, a November study by Royal Pingdom rated Facebook as the social network least likely to go down.