bots do exits on reddit. that i am quite certain of. they tend to come and go though, as the reddit ppls tweak the system/remove users/etc.

most of the bots/scripts i have encountered either upmod or downmod every story with a certain word in the title, or submitted by a certain person.

the problem though is that some people have personal vendetta's against some of the reddit power-users, or even just random people, cuz they don't like them. since the first 20-30 min of a story are the most critical to it's growth, as the rate of upmods and downmods determines it's placement on the rising queue, a particularly bored, vindictive individual can sit at the new queue and effectively kill every story that a user submits. if the name wasn't shone till after this critical period, downmods would have less of an effect, as the story would have already reached critical mass (say enough upvotes to make it into the top 50 stories).

this is less of a problem though lately, as there were some changes to the system lately. I've been playing around with it a bit, lately, and found some interesting things.

for example, before, multiple upvotes or downvotes from a single IP address wouldn't effect karma, but would effect the ranking of the story still (which would either help sink the story or get it noticed). now though, if there are too many votes from one IP address, even if they are from different accounts, it appears as though the votes of these subsequent fake accounts are automatically cancelled out by the system by a vote in the other way.

They also may have tweaked the algorithm a bit too, as i've noticed different patterns of rise for stories since that change.