In some ways, Yandex has access to more information than Google:

Along with China, Russia has long been a great big hole in Facebook’s quest to enlist users from all over the world. In late 2012, Mark Zuckerberg travelled to Moscow to meet the prime minister, Dmitry Medvedev. Zuckerberg gave him a Facebook t-shirt, but that seems not to have been enough to get Russians signing up in their droves.

Facebook stills lags behind not only VKontakte but also Odnoklassniki, another popular social network. One thing Facebook does have in its favor, however, is that it tends to be used by the most affluent and urban Russians—those who speak English, have traveled or have friends abroad. It may have fewer users, but they are more valuable to marketers. Showing off those users on Yandex could bolster Facebook’s aspirational status and help it sign up more people. 

What Yandex gets from the deal is ”full access to the social network’s ‘firehose’ of public data” from Facebook users in Russia, Ukraine, Belarus, Kazakhstan, and other former Soviet countries, according to a press release. Yandex already has access to data from Twitter, VKontakte and LiveJournal, a blogging platform which remains popular in Russia. A partnership with Facebook will allow Yandex to broaden its understanding of social conversation and to refine its results based on what people are sharing.

I really don't understand why Facebook and Google cannot be friends.

because they compete? 

Do they really? It's a big market and they both make more if they collaborate.

Then again, maybe it's better for consumers that they don't collaborate.

http://pandawhale.com/post/35706/google-apple-facebook-and-latent-search

Federated nations, Federated Tech Companies/Platforms/Databases

Right, so better for consumers if they compete instead of sharing all the things each of them knows about you. 

gotta pick a side

Is there any reason not to side with consumers?

Consumers over apple or google or other tech company/platform/fiefdom/nation?  Not sure how that would work...

It is what Ralph Nader always advocated: people before corporations.

advocated is different than implemented.