Neven Morgan, on what iMessage has meant to his texting plan:
Three months into iOS 5, I’m using a trivial quantity of text messages. I currently pay $10/month for up to 1000 messages. Assuming these bill at 20c/message (it varies depending on your plan, I’m told) I could cancel my messaging plan and end up paying less overall, even at that outrageous price. I’ll wait another two months to confirm this massive drop - then it’s time to get all Canceller Valorum on AT&T’s ass.
If you look at the graph in Neven’s post, you’ll see that his text message usage declined dramatically starting in October, when iOS 5 was released. He’s fortunate to have so many iPhone-toting friends. I’ve got a few, but not enough that it'd be worth it for me to dump my $20/mo. plan for unlimited texts. I’d love to, though. Doing so would cause my bill to drop to under $100/mo. Even better, dumping my texting plan would stick it to my carrier (AT&T), since texting plans make big money.