For those who know or have heard, I'll say "You knew this was coming". Actually I think it was seeing Dodie's avatar here that made me go "Okay! I HAVE to find out the reason for this recent MLP craze on the internet!" after seeing image macros of the ponies pop up everywhere.

Knowyourmeme actually has quite the detailed info on this phenomenon.
My Little Pony: Friendship is Magic | Know Your Meme

Too lazy to click the link and read? I'll sum it up like this:

"New MLP series done by classic CN cartoon staffers (PPG, Dexter's Lab, Samurai Jack, and Foster's) is surprisingly good and enjoyable. Becomes the biggest and most "meme-able" craze on the internet since Pokemon, if not ever."

So I told my sister about it, she was a HUGE MLP fan back in the day, and we've had a fun time watching it. I'm not going to claim something like this is the best show ever or anything like that. I'd say it's enjoyable fluff. In fact I found this article here to sorta explains the phenomenon and really shares my opinion on the series.

Just to add a little more to this thread. I've been amazed at what the fanbase have been able to conjure up. I'd have to say my favorite thing has been "DJ Brony's" Ponybeat songs which take the songs from the series and remixes them into catchy Eurobeat. I seriously can't stop listening to his Evil Enchantress remix