having it be a trailing fifty comments actually increases the incentive to avoid writing anything that won't get upvotes. Ultimately, you have to step back and

having it be a trailing fifty comments actually increases the incentive to avoid writing anything that won't get upvotes. Ultimately, you have to step back and ask whether you're trying to encourage upvotes or not. Upvotes are useful for helping readers choose what to read in a thread. But just because voting is useful for guiding the behaviour of readers... Does it automatically follow that we wish to guide the behaviour of writers? The current system of total karma encourages people to avoid comments that will get more downvotes than upvotes. Avoiding more downvotes than upvotes is not exactly the same thing as avoiding comments that won't get upvotes.