Nah, its a pretty bad idea to compare Reddit's upvotes to Merit here on the forum. Reddit's system is fundamentally broken, and is very easy to abuse. Basically, if someone wanted to they could control what is seen by others on the subreddit by creating hundreds of accounts, and down voting whatever they want. Merit here on the forum is only given to those that have earned merit or have been selected by theymos for their merit distribution, and eye for spotting posts that align to his goal on Bitcointalk, which is usually the higher quality posts.

Upvoting isn't judging the posts quality, at least that's not its intended use. Its used to help upvote content that they think is relevant, and users should see, and down vote things that they shouldn't see. That's basically it, its not really tied to the quality of the post, at least not primarily, and is only loosely associated with it. However, its most definitely misused by many of the users over there.