DIGEST.desktop 2008 allows you to annotate any amount of files on your computer. It supports both plain text and majority of the most popular formats.
Digest is an online-service allowing you to get long text compressed but still clear to be understood. It's useful when you need to understand a large amount of documents but got no time to read all of them.
getDigest "reads" the documents you're uploading and makes some analytical work based on the special algorithms. After the analysis of the text is done you're able to see the essence of the document as well as the key words of the text.