Hi Ralph!
Apparently I am in the same boat, as #hashtags are new and somewhat foreign to me and not part of my generation. Hashtags are a means of sorting or filtering out what you want to read...if you love ELS but hate discussions of #3D printers, you can use the hashtag to keep your eyes from being offended by topics that may not pertain solely to ELS. Or at least that's my understanding.
#Hashtags remind me of pointers in C in that they point to the various topics.
As for suggestions of another #hashtag, even though we are not there yet, I think #ARDuino might be a good one. It appears that an Arduino is at the core of the ELS, and if so, you will likely have to know how to compile the code without errors and upload it to the Arduino.
