Why does everyone want more personal information now?

Periodically when I sign in on Yahoo (which is rare because this place sucks now, but that's a whole different discussion) I get asked for a phone number for some security reasons. This is despite the fact I have used the site for a few years now without this being a problem. Based on what I've read elsewhere, you're required to give a phone number if you start a new e-mail account on here. I've blown it off to this point but keep waiting for the day I can no longer do that, in which case I'll no longer be using Yahoo at all.

It's not just Yahoo though. Xbox Live keeps asking for me to use a security code to verify my e-mail address-- the e-mail address I have used for 5 years to get on there. Now they want me to verify that one (which, incidentally, doesn't work, as I've done it twice and still get asked to do it) and another one. Google keeps wanting me to use my real name and basically forced me to do so at one point, before I changed my name on there to the alias I'd been using.

All of this came at about the same time. Even though these are 3 wildly different companies, I'm not sure that timing is a coincidence. But I get enough spam e-mails and phone calls as it is. I can't see why these companies I've dealt with for years suddenly need this information. What am I missing?