[maze-le]

For me they are just piling up. I usually don't delete them and have a seemingly endless list on all of my "bookmark folders" that just keeps on growing -- after a few years some url schemas change or sites go down and the bookmarks don't work any longer.

[ganzuul]

I usually clear mine by a system reinstall and forgetting about them.

No Firefox I don't actually want you to stick them in an account forever. The weight of my unfinished projects is crushing.