but the vast majority of random visits clearly come to the quick and dirty posts, the videos that I slapped up with no forethought, the items that take less than five seconds to read though often there is a video, and the occasional kitty kat.

Hm, curious. Maybe you do a better job at tagging than me, but I find those “don’t have time but need to post something” posts to be mostly ignored by randoms, and skimmed with hardly any comments by regulars, as a rule of thumb.
Maybe a scienceblogger gets more randoms naturally….