http://www.feedburner.com
- Can convert feeds on the fly from Atom to RSS - also "Smart Feed"
- Tracks subscription stats
- Allows dynamic Ad Sense? scripts
- Can combine and inject a flickr.com photo stream (always as most recent post)
http://www.feedshake.com
- Given a list of feeds, Feed Shake? will combine them chronologically into one
- Walker uses this for its combined blog feed
- Can integrate a flickr.com photo stream
- Extremely useful to aggregate similar blogs into one feed
- Allows filtering - combine blogs and only see certain posts
http://feedvalidator.org/
- Use to validate / debug your feed
http://www.technorati.com/help/tags.html
http://www.technorati.com/developers/ping/
- Info on how to make your blog automatically ping technorati - there are others you should be pinging too.