RSS and blog search engine BlogDigger provides services such as media search, link search and grouping of blog results. Media search pertains to RSS feeds on media types such as mp3, WindowsMedia, QuickTime etc. Link search provides information on sites that back link to a particular website, tracking the train of linkages among blog posts.
The Groups feature at BlogDigger allows for collaborative aggregation of RSS feeds.
A quote from the interview with Greg Gershman of BlogDigger:
There are many centralized RSS aggregators out there, but Groups is the only one that allows you to create a subscription list in a collaborative fashion. I?ve always liked the idea of combining the editable nature of wikis with the content nature of blogs, and Groups aims at that, giving you the option of allowing others to collaborate in the creation and editing of a Group by adding and deleting member blogs/feeds.
The idea was to create an open, self-organizing directory of feed groups, so people looking for blogs or feeds on a specific topic could come, search through our directory of Groups, and get a ?starter pack? of blogs on a particular topic.
BlogDigger has features for adding a toolbar and also submitting links to your blogs.
A very significant point mentioned by Greg at the end of the interview mentioned above the clear separation between metadata and content for RSS based search. It is one of the major problems with Semantic Search – how to get metadata associated with the ocean of content already on the web?