http://en.wikipedia.org/wiki/Eazel
Edit: I didn't realize they went public with such a ridiculous business plan. Dot com madness indeed ... http://www.theregister.co.uk/2000/08/22/hertzfeld_spills_all...
snort
If file manager, then they may have a Windows version too. If not, this becomes a Mac-focused article.
Terminology matters.
I don't think this app is competing against Finder as much as it is with Chrome/Firefox/Safari.
I don't believe that the growing scheme of ignoring the file system, especially on mobile devices, and in some cases even forcing you to use cloud storage (to share data between apps, for instance) is an effective solution in the short-term.
1. Don't do any Twitter or Facebook shares or likes or bullshit of any sort related to social. I want absolutely no garbage from Twitter or Facebook in my local hard drive.
2. Don't display any ads whatsoever. Price it and ask the user to buy the software. I think Sublime Text 2 does this really well.