Ummm take a chill pill folks....
Not all MP3, video files, images , text content or even torrents have been stolen/ pirated or are subject to any draconian copyright restrictions.
Provided the sites of the being searched permit the re-use of their content under some form of the Creative Commons Liscence such as the InternetArchive.com then a search script could extract and index content for display your site all perfectly legally. (torrents are a mixed bucket of worms that I'd avoid going near) . This is still technically "site - scraping" and frowned upon under the TOS here, however it never hurts to ask admin here for their opinion as such sites have a tendancy to grow rapidly and soon outstrip the facilities available under a free hosting account.
Running a search script on a free account here is not exactly easy, the ability to access an external URL was blocked some time ago to prevent wholesale site scraping so file_get_contents and cURL don't work here. There are workarounds such as the Yahoo-Pipes service that allow friendly 'scraping' (you have no control over the user agent string and it obeys the robots.txt file of a target site), this is however undergoing an overhaul/upgrade and is a little flaky at present but has been used to great effect because it's a javascript API and as such does not run on the X10 servers. It's also very easy to use with a graphical drag/drop interface for building the pipes/apps, nevertheless it's well worth a look.