Float Left isnt a very competitive search term. My keyword analysis shows around 150 searches for the term in March. Around the same for long tail terms of float left too.

It has Pr1 but only one link into the site.

Its title and meta description is probably getting it ranked #3. The site is only 2 files, one of which is the .css file, so no content either.

Only 767 pages on the Web show up as Float Left in the Title using allintitle:

Domain registered: Record created on 31-Jan-2004.

A lot of other domains containing the term float left are sub directories/pages too.

Its easy to rank for terms that nobody is searching for even if you have no content!

If you search for "robot" http://www.irobotmovie.com/ is ranked 7th on Google. That site is Flash and no content whatsover. It has a PR of 6 just because it has 6,734 links to it.