The RSS Aggregator Bloglines is starting to build a lot of whuffie on the Web and it’s justly deserved. I signed up to Bloglines at the beginning of August 2003 and at the time I raved about the benefits of having a browser-based RSS Aggregator – as opposed to the so-called “smart clients” (non-browser based apps) that Robert Scoble and others were touting. The main benefits of a web-based application like Bloglines is that you can synch your subscriptions between different computers and you don’t have to install anything on your computer(s). And since last August, Mark Fletcher has been doing an amazing job adding lots of cool functionality to Bloglines.

One such feature I discovered yesterday while browsing Sam Ruby’s weblog, in which Mark Pilgrim says in a comment:

“Bloglines puts the number of subscribers in the User-Agent when it fetches your feed, so you can see exactly how well it’s scaling. 839 Bloglines users subscribe to my Atom feed, but of course it only fetches it once.”

Well apart from being bowled over by the number of Bloglines subscribers Mark Pilgrim has (839!!), I also immediately saw simularities with Dave Winer’s“Share your OPML” service at feeds.scripting.com. Now I’m not interested in the Top 100 on feeds.scripting, I’m only interested in  viewing my subscriber list and checking to see who my subscribers have on their subscription lists, so I can discover new feeds. I have 18 subscribers at the feeds.scripting site. Not exactly A-List material, but better than a poke in the eye with a sharp stick.

So anyway, back to Sam’s weblog and Mark’s comment…I got to wondering how many Bloglines subscribers I have and how it would compare to feeds.scripting. I downloaded my latest log file from my web server, opened it up and did a “find” for the word “bloglines”. Here’s what I saw:

“Bloglines/2.0 (http://www.bloglines.com; 32 subscribers)”

Cool! So 32 Bloglines users subscribe to my Read/Write Web RSS feed. While it’s a puny figure compared to Mark Pilgrim’s 839, it is still more than I thought it would be. I’m very much a Niche Blogger (a nicer term for “C-Lister”), so I’m grateful for having any readers at all.

The difference between the count of my subscribers at feeds.scripting (18) and Bloglines (32) led me to the conclusion that Mark Fletcher could be sitting on another killer app. Because Bloglines is now so popular among bloggers (and Sam’s post just confirmed this upward trend), Bloglines could provide some very compelling weblog statistics to its users.

Think about it – while it’s easy to track our Referers and people who link to us, using Technorati, Feedster, Blogdigger and others, the one thing people want but don’t have is an easy way to track how many people subscribe to their RSS feeds. Dave Winer was the first person to provide such a service and it was another great user-friendly innovation from Dave. But it does have one flaw – it requires people to manually upload their OPML subscription files. So only those people who have done this get counted.

Bloglines however already has subscriptions data, because it’s a centralized service and all subscriptions are stored on the Bloglines server. Therefore Bloglines is able to count the number of its users who subscribe to Read/Write Web and present this data back to me.

Bloglines does currently have an option to view a list of “subscribers with public profiles” for any feed. Those who keep their subs private (the default) are not displayed. I’d like to have this service extended slightly, to tell us the number of both private and public subscribers. This protects the anonymity of the private subscribers, but gives us the figures we’re all interested in.

I’d actually like Bloglines to go further and set up a similar service to feeds.scripting, with a separate web frontend and opened up to non-Bloglines users – so they can see how many Bloglines subscribers they have. I realise they can already do this by looking at their logs, but really who bothers looking at logs apart from geeks (…oh yeh, heh, guilty as charged!). So why not slap a nice user-friendly web frontend on it?

Also I’d wager that if Bloglines had a similar service to feeds.scripting, more Bloglines users would make their subs public. I certainly would. Because it opens up possibilities for people to share their subs, find out what else their subscribers have on their lists, group their subs, etc. In other words, all the same things feeds.scripting is doing so well. And why not have an API while you’re at it, so other developers can create their own cool little apps – e.g. like Andrew Grumet has been doing with feeds.scripting.

I’ve sent Mark Fletcher a couple of emails with some ideas along these lines. I’m not sure of the technical challenges, or whether he feels it’s a path Bloglines should go down. But it seems like a logical move to provide RSS subscriber stats if you can, especially since these stats are so difficult to obtain any other way. Bloglines already seems to have more data than feeds.scripting, as evidenced by my 32 Bloglines subscribers compared to 18 feeds.scripting ones. It’s a measure of Bloglines’ popularity, but also it’s because feeds.scripting is at a disadvantage because it relies on users manually uploading subscriptions data. Bloglines already has subscriptions data, so it would be cool if it was made ‘automatic for the people’.