Stumbled on the Flight Feeder page with the great graphic showing sites vs time. Wow - somewhere around sept 2014, site addition rate took off like a rocket and has not stopped. It makes you appreciate the capacity scaling problems Flight Aware must be experiencing.
The release of the PiAware build instructions and disk image – in the pre-PiAware era it was a pain to find the right hardware and configure all the software (reading hundreds of pages of forum posts, and some wrong/misleading).