Google has long used its personalized homepage, iGoogle, as a launching point for its foray into social-networking applications. Any developer who builds an OpenSocial app, for instance, can make it work as a widget (er, gadget) on iGoogle. So far, it’s been more of a personal home page. But now iGoogle is taking another step towards becoming a full-fledged social network in its own right.

It is a tiny step, but could be indicative of the direction iGoogle is going to take. Google has opened up a sandbox for developers where they can try building some new types of iGoogle apps not available to the general iGoogle user population. Most significantly, they can add activity streams (i.e., updates) and friends lists in new navigation panes on the page. Any change in a third-party iGoogle widget will be able to be reflected in the updates pane. (This has actually been a long time coming, since adding activity streams was always part of the OpenSocial plan). And they can also play around with larger “canvas” pages that users can click through to from each widget for a full-page experience. How very Facebook of them.

Again, Google is only making these features available to developers to see what they come up with, and is not yet announcing their roll-out to the “general population.” But you can see the writing on the wall.

Here’s more info on the iGoogle APIs. And here’s a video explaining some of the new features.