In June I upgraded the Drupal version running OpenLife.cc. Unfortunately I forgot to turn on caching again - or maybe I didn't even understand it was so important. Turns out requests to the front page without caching on would easily use up 7-15% of the shared server's CPU, per request!
Due to resource starvation HostGator locked the site and immediately notified me with a ticket. After some 2 minutes of thinking I came to think about the cache, and sure enough, that was it. Due to timezone differences the site was unavailable for about 24 hours though.
Even though, want to thank the HostGator team for friendly and professional service, it was easy to find and fix the problem with the good statistics provided in their support ticket.