I don't see how you equate them making (relevant?) comments on a thread as encouraging plagiarism?
![Huh](https://bitcointalk.org/Smileys/default/huh.gif)
Did you mean shit-posting? or spamming?
![Huh](https://bitcointalk.org/Smileys/default/huh.gif)
If anything... it's simply a "Thread Bumping" service
![Undecided](https://bitcointalk.org/Smileys/default/undecided.gif)
I'd agree with most of what you said that these generally cause issues with spam, however its not unheard of for these services to copy, and paste a lot of their content. So, really its just a massive pain in the balls across the whole field. The fact that some of these services are charging hundreds of dollars to do it is absolutely absurd.