I've been a member of FT for 13 years & during that time I have actively participated on FT through my posts as well as organizing Dos. I participate in many forums, whether they be miles & points such as Marriott, United, or community oriented such as Community Buzz, Omni, Contests & Sweeps etc.
I maintain the Exec Lounge Open/Closed thread in the Marriott forum, which takes a LOT of time to update/maintain but is worth it.
http://www.flyertalk.com/forum/marri...-weekends.html
I also contribute quite a lot in the Contest & Sweeps forum (and yes, FTers do win trips!

):
Contests & Sweepstakes Forum
I organized the Presidents Day London Do for 10 years running, as well as smaller Dos.
http://www.flyertalk.com/forum/commu...idents+Weekend
I've done trip reports of hotel stays (as well as trip reports of actual travel, such as a trip to New Zealand or attending the British Oscars). Here's a hotel stay trip report.
http://www.flyertalk.com/forum/14765310-post115.html
I believe in giving back to Flyertalk via posting information that might be of assistance to other FTers, organizing Dos, providing trip reports & hotel reviews as well as being welcoming to new FTers, as I've gained so much from FT in terms of information and friendships (both virtual & in real life).
Cheers.