I wanted a way to be able to use SMS to control apps and devices around me. So, I built http://www.getsmscmd.com/ using .NET on Azure, Twilio and an MQTT broker.
I would suggest you disable the auto-playing video on your website, it's really annoying when a website does this, especially since it's so far down the page that I couldn't figure out the source of the music at first!
Sorry about that. You're absolutely right. Looks like the pages gets the last command sent. Someone had issued a "play" command and caused other pages to also get that command upon loading.
Some more info: https://github.com/dmarlow/Sms2Mqtt
http://dmarlow.github.io/