Just an additional note on the concept of texting from a computer.
SMS seems to be based on FTPing files to/from certain SMS-related servers. So it's really a simple protocol (and thus dumb/scammy that telco's charge for it).
From an automation standpoint, I have to pay more money for licensing to enable texting via my GFI fax-modem cards into order to send out SMS messages to people.
background: GFI is a company who makes fax-modem cards (like 4-8 modems in one card), so not like your old fax-modem card you used to use for dial-up internet back in the day. Businesses like mine use them to automate sending faxes to places that require documents to be faxed.
this stuff costs money for hardware, phone lines (businesses pay more than residential users) and licenses for the software and firmware for the cards.
As such, the number of people buying this and then exposing it for free is likely to be smaller than hoped for. I know I've seen sites for it when I googled, but having a sense of what it takes to do it, it's not a charity.