Something I always wondered about was the (minor) alterations made to the spider-insignia on Spidey's chest waaaaay back in the early 80s (or possibly late 70s). At some point someone made the decision to have the 4 upper legs on the spider-insignia pointing upwards, whereas prior to this change all the legs were pointing downward.
I've read pretty much every Spidey story up to and beyond that era, and definitely don't recall any in-story reason for the change. It's possible an explanation was given in a letters column, or some other source.
It's hardly as big a change as putting a yellow oval around the bat-symbol and nowhere near as major as the introduction of Spidey's black outfit a few years later. Was there one particular artist who started the trend and the rest just followed suit (as was the case with Macfarlane's big-eyes and spaghetti-webbing later on)? Maybe a new style-guide / model sheet? It's one change that seems to have stuck right up until the present.
Does anyone happen to know the official reason for the "new look"?