The bonus is that posts people vote on will be collected in a community content stream (the Top Bumped Links page).
This is kind of like a decentralised memedigger, the voting is done elsewhere, but the posts are collected into a news stream.
You can also see a stream of votes for all posts on your blog…here’s mine…I voted on one of my posts, a bit cheeky
If this had an RSS feed, I could then follow which posts of mine are being bumped in my RSS Reader, I could also re-syndicate it like a popular posts widget on my sidebar.
The only downside is that people have to register to be able to vote, although this may not be a downside, as it will prevent quick spamming.
If people do register this means they get their own user space, just like any other memedigger…see all the posts you have bumped in your blogosphere travels.
[ADDED 05/08/06: No longer have to register to vote]