Open Graph allows searching users private posts and info if they give those apps permission to do that. Google can do it. But don't you see the privacy problem of giving bunch of random companies access to all the private data? Or is Google excepted because obviously they cannot do evil?

Yeah, and like that wouldn't be a privacy problem?

How does Facebook prevent Google from indexing it? It doesn't - in fact, you can find tons of people, pages and other parts of Facebook on Google. Hell, if you want API access there's Open Graph. If you want to do large scale scraping on Facebook you can also contact then. Judging by Facebook's robot.txt, Google has this permission (and so does several other search engines).

For obvious privacy reasons? But Facebook data is public is open to everyone. For Google too. In fact you can find public Facebook pages in their normal search, too.

You obviously fail to see that people who are downloading illegally from the site are not going to be responding to this kind of questions publicly, nor do they have as much incentive to do so as non-infringing users.

The video of the proof of concept looks actually awesome, and much better than how Google is doing it now. It's also much better for the user since it pulls the content from all social networks and other relevant sites. Interestingly, they're using Google's own search engine to do this:

In my opinion this demonstrates perfectly that it's entirely possible for Google. It's just that they don't want to do it - they want more control for themselves and more information about users for advertising and marketing. Social networking would be awesome source of data for Google and they must be crying blood that they didn't get it before Facebook and Twitter surfaced. If they had their own social network they would get all that. But by far Google+ is an epic failure.

It's funny that the service is named MediaFire. This means 99% in cases copyright infringing content, at least how people use it. The rest 1% is indie and amateur stuff that almost nobody wants.

Google owns the largest site on planet that almost fully uses Flash (YouTube). You really think they're going to drop its rankings?

No, they need their service engine to make them the most money. By dropping sites that have advertisers, they're forcing people to use AdWords to get interested buyers, therefore increasing the ad click prices and the amount of advertisers they have. Don't think ever for a second that Google does this for quality purposes - they do it for their monetary benefit.

It's not about what people want, it's about what Google wants. They don't want to send people from organic results to ads owned by other ad networks, they want to send people to their own ads in search results.