I like using my firefox browser to register to a blog feed. I noticed that my blog has 3 rss feed subscriber i.e subscribe to rss 2.0, subscribe to rss 0.9 and subscribe to atom. How can I make it just one ?
You shouldn't, leave them the option to subscribe to as many different types as they want. If you make it only say Atom, you are more than likely to loose the other two subscribers. They opted for that option on purpose and for a reason, eliminating that option will eliminate them as a follower. M3rC
I would recommend moving your feed to Google Feedburner. Then you can use plugin like this http://www.google.com/support/feedburner/bin/answer.py?answer=78483&topic=13252 to help you combine all your RSS feeds into one.