It is hardly surprising that FeedBurner’s subscriber numbers can be faked. What is surprising is how easy it is to do so. As the video above shows, all you need is a Netvibes account. The folks at the Next Web in Amsterdam took a blog with 43 subscribers and turned that into 2,500 overnight simply by creating an OPML file with the same feed copied 2,500 times and pasting it into their Netvibes page. The result was 2,500 widgets of the blog feed, which FeedBurner counts as separate subscribers.
Why does this matter? Blogs like to tout how many RSS subscribers they have because, even if it is a smaller number than direct visitors to their site, it represents their most loyal readers. That’s why we display how many RSS readers we have in the Feedburner chicklet at the top of TechCrunch (currently 850,000). For these numbers to have any meaning, though, they cannot be as easy to game as the video shows. (And, no, we don’t game our numbers).
You’d think that Google would be smart enough not to double-count these things, or at least ask Netvibes and other widget start pages to de-duplicate the numbers for them by user. What appears to be happening here is that FeedBurner counts each widget for a particular feed on Netvibes as a separate subscriber, regardless of whether that widget is on ten thousand different user pages or repeated ten thousand times on the same page. The same thing happened a couple years ago with Pageflakes.
Update: Netvibes VP of Product Development Franck Mahon responds in comments that it is working to fix the problem of duplicates, but that there are other ways to “hack the numbers.” And he notes that it might be more useful to count active subscribers than just people who may have added a feed two years ago and never read it.