PDF Database: Search Engine for PDF and Doc Files

I just found a new & very useful site that can serve as an awesome reference. The PDF Database is a pdf & Word document search engine that contains over 7.5 million files that you can search for and download free.

I conducted a search for “CSS” and it quickly found 443 files. Then I did a search for “Chicago Cubs” and it retrieved 1023 files. This can be a very handy resource to find books, references, published work & anything else on the net with an extension of pdf or .doc. The site has an easy to use and attractive interface. I found it most effective when using specific searches, due to the large amount of files it finds. I downloaded a few files with no problem & will use it in the future.

What are your thoughts on this database? Who do you think this would be most useful to? Students, researchers, etc? As always, I’d love to get your take on this site or any others that are relevant.