Ask HN: What do you use to monitor site uptime?

Dead simple, you can't get much simpler than http://wasitup.com/

Three form fields. Click submit. Done. It's been monitoring my blog for the last six months

Monitorus. They use delicious periods, so I just Google it every time.

I also use http://scoutapp.com , which has saved my bacon when the problems were a little more nuanced then "the home page fails to return HTTP 200." Well worth the $20 a month if you've got a web application with paying users, in my opinion.

I use http://wasitup.com and the free version of http://pingdom.com. Both seem to work well, although Pingdom has the advantage of a monthly summary.

This is old, from the Web 1.0 world and inspired by Philip Greenspun's book "Database-Backed Web Sites" but it's dead-simple and it works:

http://uptime.openacs.org/uptime/

Oh, and it's free too.

I use nagios, and for some rails projects I use rpm (but i'm not terribly impressed with rpm), might be more worth it when we get more traffic.