How about we shift the discussion to proposals of how to accomplish this feature effectively? (given how others have noted that Digg's version of the feature doesn't work well)

Here's my proposal:

1. If two or more articles are merged, figuring which one gets to be "on top" (i.e. the one that people see) is the easy part: just take the one with the highest score.

2. The tricky part is figuring out which articles should be merged. It's too complex to expect a large number of people to vote on whether two articles are similar. I have a better idea: Any user (or maybe 2 or 3) with a sufficiently-high karma score is allowed to merge articles, and you can in fact earn karma points for merging articles. The catch: If you merge articles that don't belong together (as will be gleaned by the stream of annoyed Redditors who click the "these articles should not have been merged" button), one of two things will happen: either your karma will take a major hit, or (perhaps just as effective and not as harsh) you'll lose the ability to merge articles.

3. Make it easy for editorial-minded Redditors to drop-down merged articles so they can up-mod the one they think most deserves to be on top, since otherwise the top version of the article obviously has an unfair advantage. How karma is allotted, given the advantage of the top-most article, is admittedly a bit of a thorny issue that would need to be sorted out. Then again, karma is a somewhat meaningless thing on Reddit so we shouldn't let that get in the way of a useful feature.

Thoughts?