According to stats from FeedBurner’s official blog Burning Questions, Bloglines is the client that has the highest RSS aggregator market share, almost a third of the market or 32.86%. The statistics comes with a series of disclaimers and may be skewed in different directions, but could still serve as a useful illustration over what RSS readers are most frequently used.
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%)