I think kik is something related to Google... No idea what though, just saw this on YouTube (very rarely) in the comments and that uses Google+ now, doesn't it? Maybe it's supposed to mean "kick", just like "pushing"/"hitting" the person to notice it so it can add it to the friends list?
One can also chat (the old fashioned text way) on Skype, by the way.
Although Skype lost me after one update that came with many changes that I didn't like.
I was using MSN Messenger primarily before, then came the decision by MS to shut it down and move everyone to Skype.
Needless to say, I still can't deal with this change, I'm still using MSN, even though it is officially "closed down" for my country. Long live people with the same issue who were willing to patch it.
And I will try to use it as long as possible...
Well, you don't have to install anything and don't have to get in contact with anyone you don't want to stay in contact with. PMs might not be the fastest way of exchange (just like e-mail), so if you want that contact, you should consider to choose something that fits your needs as an instant messaging/chat program.
A rather unknown alternative is Trillian (it can connect to other instant messaging networks as well, e.g. MSN/Skype, ICQ, AIM, etc., while having an own network for itself - requires to have an account for those other networks to synch with it I think). I use it to stay in touch with those who abandoned MSN/Skype after that change.
If you don't feel comfortable about it, you don't have to do anything.
I hope that gave you an insight. 
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Diagnosed with Aspergers.
BSP-errors are awesome.