The reason why I click it is sometimes the page is still loading. I click NEW TOPIC.
But in the tiny fraction of a second that I'm clicking, all the buttons shift around as the page apparently hasn't fully loaded, placing that mark as read button right under my mouse . . .
This was the third time in two years it's happened, and it has no undo button
The way I do things, I let it say 'NEW' for any topic I haven't read, most likely because I'm not interested in it. It let's me know I haven't read it. The next time I load up a category of the forum, I just look to the last post that hasn't been read.
You could also click the middle button of your mouse on all the posts you want read, loading them as tabs, then X them out. Probably about 5 seconds of being annoyed.
Ideally, I'd like the option to turn it off for admin and let users decide for themselves. But it requires a bit of programming to do it.
I put up a poll to see what other people think.