Already posted stuff and choosing the wrong category for a thread, and especially not enforcing the correct category. There's one place for sales discussions, and that place is not said console maker's category. There's a place for discussing multiplatform games, and that place is generally not a specific console maker's category. The same goes for PC stuff as well, but it seems to be a problem mainly with console stuff. I'm pretty sure that the choice of category affects the discussion by bringing in certain kinds of people, and unless it's the point of the thread, I don't think it does anything good to the discussion.
Also, VGChartz Buddy doesn't show the icons on smaller screens, such as my laptop. Works fine on my desktop but it seems to scale horribly. I don't even get a scrollbar at the bottom to see it properly, it just cuts the icons out, rendering the buddy almost completely useless (because the icons tell when there's been new posts in a thread).
