<!-- Page cached by Boost @ 2013-11-20 12:16:50, expires @ 2013-11-20 12:26:50, lifetime 10 min -->
saw this at the end of the home pages source. I don't know a lot about code, is this serious?
Is your ISP Boost?
I means the cache expires, not the site. A cache is an in memory copy of the page on a server used to speed up access to static content. When the cache expires, it re-reads the file from disk to refresh the content. https://drupal.org/project/boost