Twitter has made a series of seemingly strange moves lately regarding their API access. First they imposed limits on third party app developers. At the time I didn’t really have a good explanation.

Today Twitter made another announcement, this time that they were shutting off Tumblr’s find your friends on Twitter features (something they’ve done to other large services like Instagram recently). Dustin Curtis has a very succinct explanation on his blog:

Twitter has an enormous advantage over Facebook in one key area: while people on Facebook tend to friend their friends, people on Twitter tend to follow their interests. The following graph from Twitter is worth far more on a per-account basis because it is directly monetizable in a way that Facebook’s generally isn’t – you can show prophylactic advertisements to Twitter users based solely on the people they follow, and probably get a much higher rate of interest. Compared to other social display ads, Twitter ads, it is rumored, work extremely well.

All of this is starting to make a little more sense now. Twitter is walling off their garden. They relied on all of these third party services for growth, but now they are in a position where they don’t think they gain as much value from the relationships, so they are ending them.

At least that’s my take. What do you think? Is something else going on here?