FileInfo.com - FileInfo is the central file extensions registry and contains a database of over 10,000 file types.
SlickReader - SlickReader is an easy and comprehensive personalization tool that allows reading the news of customer preferences and content present in the website’s feeds.
File-Extensions.org - Large computer file extension library with detailed explanation of each file type with links to download free or associated software programs.
FeedFury - FeedFury was a powerful RSS supportive tool that helped to manipulate or to retrieve content data from multiple web feeds by functioning as an XML directory, the reader, and the aggregator.
FILExt - Open, view and convert files online
Reedah - Reedah is an alternative to the Google reader that allows users to read the content of various websites, blogs, stories, articles, and many more with RSS-based aggregator efficacy.