I have noticed that people are very closed to the social media. Some people are involve in to relations with Non-mehrams. But my question is that if ladies are following shariah completely like doing hijab and do not uploading their photos on social media, so are they allowed to make relations with unknown people.
In GENERAL: Islam has many barriers...as long as you are within those barriers then you are good to go! Though distancing yourself away from those barriers would be better... as its some sort of ورع.
Specifically to your question: The barrier is to not:
- Touch a non-mahram
- Have any sort of lust for the non-mahram...or if you do by nature... just not to pursue it. So you can look into her face...talk to her... but if there is any lust in it that you fear...then don't pursue
- Not to joke with a non-Mahram
Yet on the other hand, there are some instructions to socialize with all people and all Muslims
Considering انما المومنون اخوه if you can help her out for lending her money/socializing with her just as to say 'Assalmo Alaikum (face to face or on Facebook, how are you doing today?'/ helping with any chores/sharing narrations (face to face or on Facebook) you are not committing any sin.
So by befriending her on facebook... Are you touching her? Are you somehow pleasing yourself? Are you joking with her? I don't think so! Yet if you joke with her on Facebook, then it's no good. If you do all of those mentioned in point 1 with an impure intention (نیت) then it's no good. انما الاعمال بالنیات, if you do all of that for the sake of انما المومنون اخوه then Allah will reward you! I am not saying that we should go out with the sisters and play volleyball since that isn't haram too, but very disliked... nor I am saying to never say salaam to a sister...there are barriers in Islam, as long as your are within those barriers you are good...at the same time that تقوا is important حسن خلق is also important.
One last thing... I wouldn't recommend the sort of semi-open way of socialization for all ages or all cultures...for some cultures it might be rude to befriend a non-Mahram on Facebook ...for some it might be rude to not befriend on Facebook. As long as that you are within the boundaries of Islam, then you have to use your own wisdom (عقل) to apply Islam's approach yourself
Islamically speaking, there are two certain restrictions from the Sunnah (both can be disputed) when it comes to men and women interaction, everything else is pure speculation and what could be bad for you (opinionated).
A person can not touch the skin of those who are not muharam to them
Being alone with that person - Not in public, chat rooms, etc..
The Prophet (saws) said, "Whenever a man is alone with a (non-mehram) woman, the Shaytaan makes a third." [Source: Al-Tirmidhi Hadith 3118, Narrated by Umar ibn al-Khattab]
This includes private chats, private email accounts, sitting alone in a room, etc.
Everything else is OK, like talking to a woman that is not a non muharram even if that isn't needed to (school work groups, friends, etc..). There is nothing wrong with mixes of the sexes in Islam (that is a culture forbiddance) as proved by the Sunnah of the prophet.