Conversations held through texting. These are often unnecessary and would do much better if the receiving end would just be called. Often the practicing are females with nothing better to do or males trying to get into females pants.
Sometimes textsations are used to formulate plans. However this also seems unnecesary when it might take 5 minutes to call someone to make plans rather than spending an hour through texting.
On the other hand, textsations are great if you don't want surrounding parties to hear what's being said or are in a place where calling someone isn't possible.
A textsation:
555-2143: What r u doin saturday night
555-3214: Not much
555-2143: Would u like to come party at my place
555-3214: *call*
555-2143: I'm at work
...