I’ve used the hashtag #flightlog to post information about my last two flights to Twitter:
CYRO-CYAM VFR, 4.4 hours flight time (4.2 air time) PIC #flightlog
CYTZ-CYRO IFR 1.8 PIC in a PA-28-161 #flightlog
No one is using this hashtag for anything else, and it would make it easy for pilots to find other pilots on Twitter who’ve flown the same routes or used the same airports. So far, of course, I’m the only pilot to find.