I'm probably missing something obvious but this seems to penalize genuinely active projects quite severely. Only some occasional/accidental posters (who post more than 7 days apart in the same thread) will ever be able to mini-bump the thread, is that what this is? Anybody who posts regularly (less than 7 days apart) would never bump it. Intuitively I would expect the minibump to work again once the previous minibump has fallen off the 7-day window, even if there are other posts in between.