I would mark your 'at some point' as pretty early on in the life of the WWW. When web bugs were first introduced (1995? 1997?), there was a huge hew & cry, much along the lines of what we see on HN every time Facebook does something stupid with their privacy settings. The difference is that web bugs was one of the first times some of the implications of the connectedness of the web started to break through the initial excitement/confusion about this (then) brand new thing. Now nobody blinks about web bugs (excepting that big report a while back - Wash Post? - about just how many of the things many sites use - but I don't think that report was new info to anyone involved in the tech side of the web).