there are costs to any enterprise or 'gratis' service. many such sites apparently get something from selected 'pop-ups'---penny/click? i don't know. i do know, i'm 'enabling' cookies, pop-ups on Universe Today, hoping for some contribution. i see no security risk---adaware, zone alarm, trend micro, spy-blaster keep my machines Clean.

i haven't read all your 'site-docus', so i may have missed it---if i did not, i see no reason you should not only seek contributions---but request subcribers, at least, allow 'pop-ups'. regards, and many thanks---