[contextfree]

Microsoft only follows this rule for (NT) Windows, because it was judged to have a monopoly market share. Windows Phone 7.0 and 7.5 have lots of capability accessible only to built-in apps such as Bing, for example. I guess the analogy might make sense for Google search but not the nascent Google+.

(Restricting APIs isn't necessarily just about lock-in. It's a lot easier to change an API when it affects a few teams in the same company than when it affects untold numbers of external developers. Keeping it internal for a while gives them a chance to validate, and maybe iterate on, its design. Hence some internal APIs of WP7.0 were exposed in 7.5, etc.)

[kenjackson]

The reason it makes sense for G+ isn't because of antitrust concerns, but because it would be consistent with their "do no evil" mantra.

Regarding the second point, I have no problem with Google saying these are "beta" APIs, subject to change. Their services carry this same label. As a developer I'd much rather see their full API stack, with some marked as beta, rather than a much neutered API.

With that said, I'd like to see the same for WP too, but with Google they have set a public position of doing what is right even if it is against their corporate interests -- I want them to uphold it -- not just when it is a PR win.