The folks behind FeedBurner have a blog post about RSS Market Share which discusses the distribution of aggregators they see polling their most popular feeds. They write

...RSS Client market is not yet consolidating, it's expanding. There were 409 different clients polling the top 800 FeedBurner feeds in September and now there are 719 different clients. FeedBurner actively catalogs the behavior and specifications for hundreds of these user-agents...

...This list is heavily skewed toward aggregators used on blog feeds, since most of our feeds are from blogs. This list might read quite differently for more traditional media feeds such as Reuters, NYT, CNET, etc. On a similar theme, individual publishers will notice that the overall market share may be wildly different from their own feed's market share. Simply removing our top 10 feeds from this data results in a wildly different market share list, possibly because of clients that ship with one or more of our top 10 feeds as a default. All of this pointing to the caution not to read too much into this single data point. We could make qualifications about everything on the list. Your mileage may vary, caveat emptor, mea culpa, c'est la vie..

Top 20 RSS clients across FeedBurner most highly subscribed 800 feeds as of January 6, 2005

Aggregator Name (Market Share Percentage)
1. Bloglines (32.86%)
2. NetNewsWire (16.95%)
3. Firefox Live Bookmarks (7.78%)
4. Pluck (7.20%)
5. NewsGator Online(4.45%)
6. (not identified) (4.07%)*
7. FeedDemon (3.83%)
8. SharpReader (3.27%)
9. My Yahoo (2.58%)
10. iPodder (2.42%)
11. NewsGator (2.23%)
12. Thunderbird (2.13%)
13. RSS Bandit (1.12%)
14. NewsFire (1.05%)
15. iPodderX (1.02%)
16. Sage (0.71%)
17. FeedReader (0.67%)
18. RssReader (0.54%)
19. LiveJournal (0.46%)
20. Opera RSS Reader (0.45%)

Although interesting, their numbers probably aren't reflective of the reality of the RSS aggregator market share. LiveJournal has over 5 million accounts with at least half of them being active users. I suspect there are far more people using their LiveJournal friends page as an RSS aggregator than the entire top 10 list combined.

However this does bring up a question I've been considering for a while. What should be the default feeds in an RSS Bandit installation? Besides the various RSS Bandit feeds we also subscribe the user to the RSS feeds for Microsoft Watch, Yahoo! News, BBC, Rolling Stone, Slashdot, Boing Boing and InstaPundit. I've been considering removing a few of these feeds such as InstaPundit since I don't read it regularly but the one or two times I've read it I didn't think much of it. I've also considered adding more blogs I read such as Robert Scoble or Dave Winer.  

Given that RSS Bandit is moderately popular with about 50,000 downloads of the most recent version and about 130,000 total downloads over the past year I'm sure we'd be contributing a decent amount of readership to whatever feeds we install as default. Therefore I'd like some ideas from our users on what you think the best mix of feeds should be for folks installing RSS Bandit for the first time which in certain cases may be their first RSS aggregator.