If/when a thread gets updated, it goes to the top of the list. This current setup is very annoying and is geared toward those who 'live' at the site. Many times I'll see threads that are 3 or more days old that I could reply to and possibly help out a fellow hobbyist - but why bother? Most people aren't going to look. And I know it's possible because other forums for other activities I participate in offer it.