In my point of views sarcastic comments comes along with some general questions. As

1) who did the comment?

2) The degree of commenter.

3) In what prospective the comment is being given?

These are some basic questions are to be resolved by anyone who is seeking to argue over the topic. As if the comment is in the form of backbiting,everyone likes to forget about it because in my opinion if someone has guts to say something openly can only comment sarcastically.

As well as the degree of the commenter plays an important roll.

Thus in my opinion sarcastic comments are lovely if used for other as well as used by other for us.

Definitely 'NO' in my opinion. Because billions of people using face book this time and you can never guess about their ages.

First point polygamy is certainly an illegal act in some countries like India,Pakistan etc.

Polygamy is allowed, under certain circumstances in countries that are Muslim religious but not in all Muslim countries. In secular Muslim countries such as Turkey, it isn't allowed.

Second point it's a social networking site,people get here for different purposes like business dealing friendships chatting etc but not for marrying. If anyone practicing this he/she will defiantly think for several time before doing this and thus it can be emerged some cases of fraud resulting Face book prestige down.

Thus in my opinion Face book never accept Polygamy. :)