Why would you ignore them? Why not skip them?
You don't have to shift through a constant stream of **** to put it simply

No point reading peoples posts like d.p., floppers, lambchops, doom etc. their posts offer absolutely nothing to this forum/thread.
I think using an ignore list is silly, One day you may post for help with a problem and get given the answer you need but, you'll never see it. It's much safer to simply not read posts from those you consider trolls.
In that case, you create a new thread and when you scroll to the bottom, click on show ignored content.
Also, from what I've seen, d.p., flopper, doom etc. don't post in many other sub forums/threads or/and don't post anything in sub forums that I visit so no real loss either way.