Text messaging is bad for setting up dates, confirming, and for almost anything else relating to DJ'ing for the following reasons:
1) Takes lots more time than a phone call from the phone you're using for a text message.
2) You have the possibility of no response from her for a myriad of reasons.
3) There is much less emotion in reading words on your cell phone than hearing them.
Face it, for anything relating to DJ'ing text messaging, be it on a cell phone or on a computer, is horrible in comparison to talking in person or on the phone. Text messaging on a phone should be used only, and sparingly, in places where talking isn't allowed (libraries, certain government buildings, child-labor sweatshops, etc.) or when the other person is away from their phone, because otherwise you can (and most likely will) get ahold of them by calling.
But text messaging serves its purposes outside of the DJ'ing realm, don't get me wrong. Instant communication between you and whoever has your screename, allowing other people who don't have the guts to use a phone to contact you, and most importantly chat-rooms (which are hard to do on a phone or at any time in real life without planning) make text messaging good for communication.
All in all, what I've said is:
Text messaging is BAD for macking, but it is GOOD for communication.