[onion2k]

"Number of users per day" is a vanity metric. It doesn't matter to a business like Yahoo. The thing that actually matters is whether or not those particular users make money for Yahoo. If they're run the numbers and discovered that Facebook users don't turn in to paying subscribers or click on adverts (and they can't find a way to do that) yet cost them $0.25 per day in bandwidth then turning off Facebook login will increase their profits by £200k/month due to the saving.

[laumars]

I don't think this is a short term profit-based decision like your example suggests. I think this move is done to convert some Flickr users over to Yahoo!'s own passports rather than promote their competitors.

There was a time (back in the 90s) when Yahoo! logins offered more services than Google accounts. I'd be surprised if Yahoo! didn't see getting back on top as an eventual end goal (even if it seems rather optimistic at the moment). So it would make sense not to have competitors linked into their own resources when they have their own passports already.

[Ntrails]

I assume that they are also handing over data to Facebook with every auth that helps the competition with targeted advertising revenue?

[mrobert]

That would be a correct assumption.

[mmmooo]

definitely a fair point, though personally, based on absolutely nothing, I don't think it is likely that 'those that login via facebook/google' have a drastically different behavior pattern (when it comes to stuff like paying or clicking). Would love to see anyone that has any such data.