why migrate to QATO and not stay with the tried and proven and known

StackOverFlow doesn't seem to be causing problems, is the "goto" programming question site. So why the switch? Unity Technologies not pay it's bill? Qato offer to host for free?

If anything, why not upgrade to the latest and greatest version of stackoverflow. Or maybe even a beta version with increased features.

Is Qato made up of disgruntled former StackOverFlow staff?

What gives for this dramatic changeover.

Most importantly. My favorites. I've been using them as bookmarking. They still gonna be there?

From this answer...

For the interested, StackExchange, who currently host answers.unity3d.com have changed their business model and will close down the site. Because of this we are moving the site over to the good people at dZone, who have a solution called QATO. The downtime next week is to allow us to migrate the database from SE to QATO. Once the migration is done answers.unity3d.com will reappear. It'll look pretty much the same with a few cosmetic changes.