Hangouts clients talk HTTP or some network protocol, not Borg/Spanner/GoogleDataCenterMagic
Google doesn't need to build open-source apps, just give users a documented way to send messages on their own accounts to the Talk system.
At most, the extra engineering effort is to implement an authorization and rate-limiting (anti-DOS/spam) system that doesn't depend on obscurity-via-closed-source-client. Most of that probably already exists, for obvious reasons (attackers).
Federation is a different problem, because Google has less control over off-network spammers. Personally, I think it's fine to say that if you want to talk to Google Hangouts users, you need to create a Google account for that purpose. But it would be less evil to have a system by which trusted developers could interoperate, as long as the "trust" filter is non-discriminatory. (Any reasonably public/accountable organization can get an interop key.)
And Google should provide a way for users to send Hangout calls to other servers that choose to implement the Hangout protocol and accept incoming connections from Google, a trusted network. Doing so in its first-party app would be non-evil.
That's not arbitrage, that's like poker: players gamble against each other (effectively betting on what other people will bet on, with a bit randomization in the mix), house takes a cut of all the action.
Another horrible repeating of the "income inequality" trope, and then showing graphs of median income that don't get near the top l% of US earners, while citing a stat that the top 1% of earners are gaining.
> You are asking, gwern, a question about what people like about your writings.
tokenadult, do you have an Ed.D or Ph.D in Education? Or maybe something related to Social Work?
Did you know that this communication style, which you use rather consistently in your HN posts, and which is prevalent in the education community, is poorly-received rather outside that community?
Not saying your style is wrong, just that is extremely grating outside the Ed world. It sits in the uncanny valley of faux-familiarity, and as such it breeds mistrust.