Our favorite Mac site monitoring tool. Solid, dependable, full of notifications when checking sites. Tracks sites, servers, forums posts, comments on blogs, even checks web mail.

It checks servers for changes or failures, and notifies you via e-mail, sound, speech, Twitter, or other means. You can use it to track updated sites, and to alert you when an important server goes down or recovers.

9WR - Dejal Simon: Server monitor tracks failures, notifies via email, alerts, Twitter.