Tool or website to easily check what a website was developed in?

I realize you can look in the source code and do keyword searches, but that can be time consuming, and not altogether accurate.

I am just wondering if there is a tool or website that will do that kind of check for you and report back and tell you what it was developed in, and maybe even what version? Joomla? Drupal? Wordpress? Etc.

Thanks!

There's a Firefox addon that does it, but I don't remember the name. It does it by looking at the source code, so obviously it's not going to be any more accurate than doing that by hand, just more convenient.

Thanks! I found it! The extension is called wappalyzer.