The answer to this should be easy. What are the APIs exposed to Google developers.
In the MS antitrust case one of the important things that came out of it was that internal MS developers had access to the same set of APIs to Windows as 3rd party developers. That is, the CLR or Excel or Sharepoint, for example, don't have access to special APIs that no one else has access to.
Google should do the same. Anything that GMail, Search, Docs, have acess to, so should Facebook, Bing, and Twitter.
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.)
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.
In the MS antitrust case one of the important things that came out of it was that internal MS developers had access to the same set of APIs to Windows as 3rd party developers. That is, the CLR or Excel or Sharepoint, for example, don't have access to special APIs that no one else has access to.
Google should do the same. Anything that GMail, Search, Docs, have acess to, so should Facebook, Bing, and Twitter.