Community Tip - Your Friends List is a way to easily have access to the community members that you interact with the most! X
option 3 Custom Queue job on schedule queue seems to be the good option.
see this posthttp://portal.ptcuser.org/p/fo/st/topic=16&post=124498#p124498 some companies are using this option.
option 1: is simple option but it may run into some performance issue because of sync and timer robot .
Thanks,
Shreyas