OPML for Twitter subscription lists 

This howto describes a web service that generates OPML Subscription Lists for Twitter users in a form that can be imported into a feed reader such as River2 or Google Reader.

It has a limit of 1000 followers. If you want an unlimited version you can download the app and run the software on your system.

Demos 

Now with that important disclaimer out of the way, here's the service:

http://tw.opml.org/get?user=cluelessnewbie

That returns the OPML Subscription List for the Twitter user named cluelessnewbie. This person subscribes to the top 100 most-followed people on Twitter (that's what makes him so clueless).

You can change the user to any Twitter user you like and you will see the OPML subscription list for that user.

For example, Jay Rosen, my partner in Rebooting The News podcast, carefully grooms his follower list to provide a good cross-section of thought on journalism on the Internet. HIs subscription list is:

http://tw.opml.org/get?user=jayrosen_nyu

More examples: Danny Sullivan. The Gillmor Gang. Gruber. Om. Loic. Doc Searls. Anil Dash.

How it works 

Before it generates the OPML, it makes a series of calls through the Twitter API to find out who the user is subscribed to. Twitter only returns 100 names at a time, so if the user subscribes to 1000 people, it has to make 10 calls. This can take a few seconds.

To keep the traffic to twitter.com relatively low, we cache the result for up to one hour. So if you follow or unfollow people, it may take as much as an hour for the OPML to reflect the changes.

What it's good for 

You could use this format to import your subscription list into another app, if one existed. As far as I know none does exist. However, this is an essential step in a bootstrap to create new ways of consuming Twitter data.

I'll have more notes here as they develop, and please post questions if you have them.

Quote 

I sent a preview link to Anil Dash and here's what he said: "Heh. This got one of those immediate belly laughs that only come from seeing something new and realizing exactly how disruptive it can be. "

If you can't see the OPML... 

If you're not using Firefox/Mac, the OPML may render weirdly in the browser. If you're not sure what you're seeing is right (this is roughly what it should look like), do this:

1. Choose Save As from your browser's File menu.

2. Save it to a local text file.

3. Open the file with a text editor.

4. You should now be able to see everything that's in the file.

Basically some browsers do funny things with the XML. (Probably my fault, but IWOMM.)

If you follow more than 1000 people 

I added a limit of 1000 because some people follow a lot of people, and this is just a test.

So if you follow more than 1000, you'll just get the first 1000. Sorry if you were looking for more. When I release the source you'll get it all.

Importing Twitter subscriptions into Google Reader 

Matt Mullenweg had the idea to import his Twitter subscription list into Google Reader. It worked, but all the subscriptions imported at the top level, meaning he had a clean-up to do.

So I added a feature to the app, if you add "&folder;=1" to the end of the URL it creates an extra level in the OPML, designed for import into Google Reader (and probably other RSS aggregators as well). Example:

http://tw.opml.org/get?user=jkottke&folder;=1

Step-by-step instructions...

1. Save the list to your desktop.

2. In Google Reader, click on Settings (in the upper-right corner of the window), then Import/Export.

3. Click the Browse button and choose the file you saved above.

4. Click the Upload button.

5. When you return to the Google Reader main page, you'll see a new top-level section for your Twitter subscriptions.

Now you can follow Twitter folk in Google Reader. Heh.

Links 

Marshall Kirkpatrick at ReadWriteWeb wrote a great tutorial for this app.

OPML 2.0 spec.

Log of requests made to and by the app.

This is part of the rssCloud project.