Outernet is very interesting and I can only hope it will develop with time. However there are many great technologies that already exists and if you have the right equipment you can try them out right now. Below is an example of 2 way E-mail via Ham Radio.
Found this example although a little boring the tech behind it is amazing:
This is not my video but it is a great start.
There is also a project from 2012 called OneBeep. The software is ready and tested. It pretty much does what Outernet is able to do right now but with AM and FM radio. Only requires a radio a laptop and a 3.5 male to male cable.
Not to mention onebeep a software that downloads via radio
E-mail can also be sent for free via Satellite however I belive it is one way and only one line of text. Document link below: