Is it legal how Facebook follows me around on Y/A and snoops through my email?

[Think about it]

Whatever topics I write about on Yahoo Answers, I see them as advertisements on my facebook page. For example last night I asked a question about getting a personal trainer, and today all the ads to the right of my Facebook are about personal trainers. Same with internet searches. It just follows me around outside Facebook like it has rigged my whole computer and reads everything I type. It does that for email too but I'm sure everyone's noticed that. Isn't that invasion of privacy? Is it legal?

It also recommends friends from my address book in my email box on Google and Yahoo. That was the first thing that creeped me out and I complained to FB about but there's no way to stop it.
Travis - I never see a Facebook logo with a box when I ask questions. I just asked one to double check and nope, there are no logos when I ask or options to deselect!!!
danny - I've already ex-d to remove all the apps, that's why I am complaining - it is doing it against my wishes/consent. I'm supposed to think it miraculously/conicidentally just reads my mind and knows what to advertise to me but I see a pattern that it's whatever I post about on YA and other websites.

[Computer ER]

This is the beauty of social networking.Read before you click.

[Travis]

When you ask/answer an question on Yahoo Answers, it automatically sends to Facebook. You can stop this by (when you finishing asking/answering a question) un-selecting the little box that has a pic of the facebook logo next to it. This will make is so that it doesn't send any info about this question/answer with facebook.

[dannyboy2111]

yes its Legal If you Dont want Yahoo Answers to Send Stuff or Access your Facebook anymore you can Remove it Go to Privacy Settings Than App/websites than Find the App and Hit the X button and you can Revoke it