This is what I imagined the thumbs-up/down on a profile would do. If a person with lots of karma gives you a thumbs-up, you get more karma than if someone with little karma gives you a thumbs-up. However, lots of low level users giving you a thumbs-up would equate with a single mid-level person.

However, I don't think it was implemented, and the profile thumbs up/down were removed.

[Which reminds me, if there's more midgard work to be done, karma calculations need a re-architect so that everything isn't scanned every update, so that a) there won't be sudden shifts if one source is down; b) updates are more timely and c) karma decay can be implemented]