The Internet is a tool of connection and connectivity, giving the valuable information to whom can benefit from and pursue to trace out the good information. As the Net forms a big social fiber lacking the rules and the norms, it  so important to clarify one its remarkable sides- the social relationships which may be held between the  youth of the two genders.
No doubt that the Muslim woman can make use of the Net as long as this will not lead to an unlawful action, like chatting with the foreign men, considering the bad consequences of this chatting that may call for the temptation and admiration. Thus, the strictness is a must in this regard; avoiding this tarp is, for the sake of Allah,  an necessity.
The on-line chatting causes the wickedness and vices to its doers to the extent that they fall in love and adoration; it leads them to the worse as Satan deluding the parties of the chatting, spoiling the worldly and hereafter matters in one \'s heart.  
The Islamic law (Shari\'a) closes all the doors   leading a man to the trap of the temptation; thus, it forbids the privacy meeting between a man and a foreign woman.
Needless to say that the private conversations can not be regarded as a pure privacy meeting between a man and a woman; but it may be a cause of the wicked temptation as it is known.
Some can account for the relationships held with the other sex, like discussing the allowable topics, calling to Alalh,etc.
But as we live in a time of various types of seduction and temptation, and as the temptation is so fatal to the young men and women, taking into consideration the Satan who makes the vices more attractive and allowable before the youth, the young men and women may commit vices fancying they do good.
Further, the conversation between a young man and young woman may cause dubiosity to the seer who will not think about the good intentions of this conversation, like advice and the preachment; the seer may expect that the two parties of the conversation are wooing each other. 
For this reason and others, it is not allowable for the young woman, in particular, to converse with a young man even for the sake of advising. There are accidents of young women who fall in the vice because of this matter. Our Prophet (may peace be upon him) is right when he says, \"There is no privacy between a man and a woman without the presence of the Satan\", and he also says,\" The Satan runs in a man\'s blood\".
Sheikh Ibn Jubreen ( ay Allah save him) was once asked,\" What is the judgment of  the pen friendship between the young men and young women, taking into account that this kind of correspondence is free of the loving, adultery and whims?\".
He replies,
\"It is not allowable for a man to pen friend any foreign woman because this may lead to the temptation. The correspondent may fancy that there is no temptation, but the Satan will persist to attract him/ her to the trap of the temptation\".
Similarly, the Messenger orders us to avoid the Deceiver (Dajjal) once we hear of him; he may persistently inflict a believer man.
The correspondence between the young men and young woman bears a great danger of the temptation that should be entirely avoided even this correspondence is free of any inclination to love or adoration.
In conclusion, the on-line chatting is more fatal and dangerous than the traditional pen friendship.