Personally, I consider it disrespectful to your fellow Hounds to start a new thread on a non-time-sensitive subject without first searching for a previous one on that subject and adding your thoughts to IT instead.
Likewise, to add a post to a thread without first reading the previous comments. If I agree with one or more of these and have nothing new or different to add, I click the recommend button on those that say what I would have, rather than posting a separate "+1". It appears to me that the number of those has decreased since Hounds have begun noticing and using the recommend feature.
On the other hand, some threads get very long, to the point where reading all the comments before posting becomes overly burdensome. Do you have your own "cut-off" number, and if so, what is it? I seem to read 50-100, depending on how many long vs. brief posts there are, then skimming the rest, before weighing in if my viewpoint/suggestion is not already included.
Just the other day, the 15th on a thread of brief posts repeated all the answers from the first 14. Does Poster 15 not bother to read the thread, or is s/he a digital Narcissus, someone who loves the sound of their own typing? Ooh, a new neologism: internarcissus. I've got a little (mental) list, of Chowholes, and it's got a new member.
End of rant.