You should really do some research and find out what the good granny paysites are, so you can promote stuff that sells. I'd recommend checking out some review sites to see their mature sections, even as far back as milf aged to find good paysites.
http://www.adultsitesurfer.com/categ...ilf/index.html
http://www.thebestporn.com/categorie...s/mature_porn/
http://www.porninspector.com/reviews...y/older-women/
Also do some research on what keywords are mostly used in regards to mature porn, like tarts, granny, older women, old ladies, mature, milf, grey hair, white hair, wrinkles, wrinkled pussy, flabby tits, etc.