It might be a good exercise to chase down old posts of people who wrote the first browser toolbars, as well as the browser infrastructure that made them possible. We can contrast the speculation on why they might have been a good idea with the actual result. Not as a way to trash them, but as an exercise in how smart people can miss the mark.
More popular if done as a way to trash them, I expect. You could make "trash old usenet posts".com and have a ranking system for "worst decisions ever".
(C.A.R Hoare's billion dollar mistake, for example).
