I'm running a site now that has a chat room (using Cometchat) and 3 embedded live cams showing activity in 3 bird nests (great blue heron in upstate NY, red-tailed hawks in NYC, and bald eagles in Iowa). My users would like to be able to send a quick SMS and email to other members when they see something exciting starting to happen in one of the nests, like an egg starting to hatch.
This should be opt-in, from a form. I don't want every registered user/member to get such an alert, only the ones who have specifically opt-in for this. And the alert has to go out immediately, given the time-sensitive nature of the event. I've found that email alerts/newsletters run through the WP system can take a long time to actually go out.