I used to use stumbleupon a lot. I had an xmarks account for bookmark syncing before that went paid for. I now just use Firefox's built in syncing service.

Having never seen the point of a social bookmarking service can someone tell me reasons why I should consider using something like this? What were the benefits over my private bookmarks. I obviously remember it back in the day but viewed it the same I do most social networks, with suspicion.