John Borthwick has been advising companies for a while now to build APIs that mimic the Twitter API. His reasoning is that if your API look and feels similar to the Twitter API then third party developers will have an easier time adopting it and building to it. Makes sense to me.
via www.avc.com

There was a great thread on AVC this week on the impact of Twitter's API specs being reused by others (check out the lengthy comments thread as well). I think this is the beginning of a trend and we'll see a lot more of it in different types of apps:

• APIs for different content types are likely to come in similar forms (there just aren't that many ways to build a half-way efficient blogging API).
• Familiarity helps adoption and reduces friction for everybody
• Although different services often have unique features there's likely to be a "common core"

Actual standardization (W3C et. al.) is probably not on the cards right now but some convergence looks inevitable and beneficial to all. There are two interesting dimensions to look at:

• Convergence by application/content type: where you could see standard patterns emerging to for video, audio, messaging, blog posting, news etc.
• Convergence by individual type of operation: e.g. user account creation, payment, creation of relationships (friend, follow...), search etc.

In the second case building blocks can be recompiled into complete APIs.

I hope we see more moves in this direction since it will reduce friction in API provision and usage - making it easier for everybody to focus on the business of building great apps with third party APIs.