A Google search for "leave" still reflects the time when most porn sites had "age verification" on their front pages. "Age verification" often took the form of the text "You must be 18 to enter" followed by "Enter" and "Leave" links. The "Leave" link would often lead to a site appropriate for young kids or to a sex-education site.
Even today, when few new sites follow this practice, "Leave No Trace" and "Leave It To Beaver" are beaten by Yahoo, Google, Scarleteen, and Disney.
I wondered why Google's algorithm continued to make this possible despite tweaks to prevent Googlebombs such as "miserable failure". I came across this comment by Google engineer Matt Cutts:
[The algorithm change] really does have a very limited scope and doesn’t affect a large fraction of queries. The intent of the algorithm is to minimize the impact of “true” Googlebombs, which occur when someone is causing someone else’s page to rank for stuff that they wouldn’t want to rank for themselves. The algorithm could detect phrases such as [leave] as a Googlebomb in future iterations, but it doesn’t right now and I don’t think that Disney would care much either way.
Googlebombs were slightly embarrassing, but I imagine that abandoning link text would have hurt search quality a lot. I'm impressed that Google was able to come up with an algorithmic way to distinguish Googlebombs from other link text.