What is the disadvantage of just using email addresses? Virtually every wireless company provides an email to sms gateway which basically gives each phone an email address. My current startup uses email addresses for 2 way interaction with the system via text messages so while slightly more difficult to configure initially, it's free!
Free yes, but as someone else mentioned, you don't have any guarantee of service quality. We used email-to-sms when prototyping Padpaw and got mixed results on message delivery. This is an important requirement as we're sending out change of event (i.e. "game rained out") messages. Also, using SMS for signup is a lot more straightforward for people - they can send it right from the phone.
Doesn't this require you to know which provider owns each number? We'd been considering going down that path, but couldn't find any decent way around it (and I don't consider asking customers which provider they're on decent.)
TMobile drops some of those at times. I'm not sure if it's just low priority or they randomly throw them away. It drops them outside of busy times, like late at night also.
the problem is that the cell carriers are also aware of this and from what I've heard from some people, unless you're yahoo they may block your mass company emails
are you doing this on a big scale yet? if so please share any other tips (especially on not getting blocked)
Not sure why they would block your messages. As long as they aren't spam (don't send unless the user opts in), then the cell provider makes 10-15 cents on every message you send. They should be more than happy to transport the messages for you.
