Everyone has their own way of speaking- or typing. Even if it's not always grammatically correct. I try to just ignore it, as I'm too shy to correct them, especially if it's one of my friends. xD
If I think about it, this is somewhat similar to the word "Ain't". People use it, but it's not correct to really use... So yeah, I don't know, most people figure these things out on their own though, or just use it because they think it's cool to do so... Well, the "le" fad has calmed down a lot actually from how I've seen it be in the past. :I