Thanks for the praise, I know it's not a super huge scale project but it was a good challenge to develop. As far as speed goes, I'm not exactly sure. I know that Twilio's toll free numbers send about 5 SMS messages a second, so once many users use the app at once it would slow down significantly. One thing I'm working on is decentralizing the app so that a Server Android app could be run on a phone that has an internet connection, using that phone's phone number as a way to send pages. About speed, I just ran a test and checked google.com's file size (it's 112 bytes) and timed the page request, upon the first text arriving it only took 4.5 seconds to load. That's a staggering 40kbps! Pretty impressive as a best case scenario, but a bunch of factors will probably make the average a bit lower.