IMO, it's someone who regularly takes part in discussions and events. I wouldn't call someone who posts 20 replies in a week and then nothing for 6 months an active member whereas someone who posts a couple of times a week probably is. A steady input rather than binge posting denotes an active member I reckon.
Thanks for the tip. They came in way cheaper than anyone else at £679, which includes 5 track days as well at approved tracks. Everything else excatly the same as my previous insurers with a slightly reduced excess. That's over £200 cheaper than renewal price.