Is there a community driven unified article database? I am using Mendeley to keep track of my papers. It allows me to group the papers in folders, and I can easily export BiBTeX for a folder which I can include in a paper I am writing. 

However, almost always I need to fill in all the details when I add a new paper to my library. "Search by Title" feature does not do a great job.

I think everyone around the world is creating their BiBTeX (or any other format) entries by hand. Is there a community driven (wikipedia like) website/service that unifies this process?

What I have in my mind is something like this: People add article meta information (title, authors, year etc.) to this public DB, if they see a mistake they correct it, if they see duplicates they prevent it by deleting one. And one can export entries as BiBTeX, etc.

The closest thing I saw is Google Scholar. But because it tries to automate nearly the whole process there are still lots of mistakes.
Sadly, not yet...

Many publishers view their bibliographic metadata as commercial property and hold-on to it fairly tightly.

Mendeley will release little bits of the article data they have accumulated from all their users, but they will not let anyone download all of it - it's valuable property that they want to keep 'in-house'.

There are a few truly community-driven projects trying to change this e.g. Open Citations &amp; Open Citagora.

These projects aim to build truly public &amp; open databases for anyone to build upon &amp; annotate. The other tools mentioned in the question aren't really public or fully open.