The web is more interesting when you can build apps that easily interact with your friends and colleagues. But with the trend towards more social applications also comes a growing list of site-specific APIs that developers must learn.

OpenSocial provides a common set of APIs for social applications across multiple websites. With standard JavaScript and HTML, developers can create apps that access a social network's friends and update feeds.

It was only a few months ago that I wrote:

Now is the time for all good men to quit their silos and adopt an open standard.

FC has a roundup; Steven Johnson says:

What a brilliant move by Google. (I suppose as a launch partner, I'm biased, but still: what a brilliant move.) That $15 billion Facebook valuation got a lot of abuse over the past few weeks, but in a way I thought it made sense. Obviously, there was risk involved, but if you thought that Facebook had a reasonable shot at becoming "the social operating system of the Web", then it was probably worth making the bet -- particularly given that Microsoft had other reasons to invest. A company that runs the web's "social operating system" could easily be worth $50B or $100B. But that seems entirely impossible now, just a few days later, thanks to OpenSocial.

Not everyone is so sanguine:

“Open Social” sounds a lot like an “Open Marriage” – on the surface some may think this sounds fun but after thinking about it for a minute you quickly realize it’s a bad idea.

NYT observes:

Developers may not see the advantage to writing programs that run across such remarkably different networks.

But Eric Schmidt is reassuring:

"If you are of a certain age, you sort of dismiss this as college kids or teenagers. But it is very real."

OpenSocial