Brian Livingston at Datamation looks at some data provided by Feedburner based on the 70,000 RSS feeds they manage (via Dan Gillmore).  The data tells quite a story regarding the distribution of the RSS aggregator market.

There are two tables of data, the first is the distribution of RSS aggregators pinging the top 1,000 feeds by circulation.  My Yahoo is top with 59%, then Bloglines with 10.4% and Firefox Live bookmarks coming third 4.2%.  Beyond that there is a steady trickle down for the next 17 aggregators sharing the remaining 25%.

The second table is really interesting.

This is the distribution of RSS aggregators pinging all 70,000 RSS feeds except for the top 10.  The list of aggregators make up 87.2%.  It takes 11 RSS aggregators to reach 75% of total known market share, top being Bloglines with 19.4%.

So, all early days in the RSS aggregator market.  As Eric Lunt, co-founder and CTO of Feeburner says in the interview:

''The market becomes more and more fragmented every time we measure it, which indicates that we're still very much on the innovation upswing,'' Lunt says.

Table 2: Top 20 RSS Readers (excluding 10 most popular feeds)

Bloglines 19.49
NetNewsWire 10.07
iTunes 9.53
Firefox Live Bookmarks  7.25
iPodder 7.17
My Yahoo 6.68
FeedDemon 4.23
NewsGator Online 3.83
Reader not identified 3.07
Pluck 2.07
SharpReader 1.91
iPodderX 1.77
Thunderbird 1.75
Safari RSS 1.75
LiveJournal 1.44
NewsGator Outlook Edition 1.27
Apple CFNetwork Generic Client 1.21
RSS Bandit 0.99
Opera RSS Reader 0.9
Sage  0.82
TOTAL 87.2