Can I find out someones IP address from through facebook or if I know their email?

[MikaSch]

It may not be too easy to find anyone's I.P address. Sure I.P address change but not as constantly as one likes to think or one is told that it does. l have the same I.P address for quite sometimes now. To find the I.P address of a person you will nerd the backing of Law. Even the law Officers cannot call up the Internet Service provider and demand the I.P address of anyone at random or at their whim. They need specific orders from a judge or someone.
The way things stand in USA now most of the I.P addresses and all are being routinely snooped upon by the NSA / FBI and the likes.
As long as this so called 'someone' from Facebook is not bothering you too much and as long as this person has not acted like a creep, then you can maybe slowly put more distance (as in distant connection) between yourself and him, to be on the safe side..