In other words, if you’ve added your blog’s RSS feed as one of your services on FriendFeed, all of your FriendFeed subscribers will now count as RSS subscribers in FeedBurner. FeedBurner essentially treats FriendFeed as another RSS reader, so you see its subscription count side-by-side with subscription counts from Google Reader, Bloglines, and other tools that people use to read your blog.
You can see this in the distribution chart for a rarely updated personal blog of mine, where I suddenly have more than 2,000 subscribers, almost exclusively thanks to the inclusion of my FriendFeed followers:
This change will certainly make your blog’s RSS chiclet happy, and does provide a better measure of your total reach. However, one has to wonder if this number is starting to lose relevance. Beyond FriendFeed, people are essentially subscribing to blogs on Twitter, Facebook, and dozens of other smaller social sites that let bloggers syndicate their feed. Not to mention, the FeedBurner number likely includes lots of double counting - i.e. - people who subscribe to your blog via multiple tools.
Perhaps a new measure of publisher influence is needed – one that combines all of these numbers as well as looks at other metrics like engagement. Until then, enjoy your inflated RSS numbers!