Sure, I'll contribute to that Wiki page when it's up.
For now:
"Today" -> "Vandaag"
"Yesterday" -> "Gisteren"
"Active forum threads"-> "Actieve threads" (could be "forum threads", but I think that's a bit too verbose)
I'm not sure about "Aantal keer bekeken", by the way. Maybe it should be "Aantal keren bekeken", but I'm not sure what the grammatical rules for that are. Maybe the other Dutch speaking niners have better input.
I'm not sure how you'd want to address users, by the way. "What you are watching" is currently "Waar u naar kijkt", but that's a pretty polite, formal way of addressing people. If you want to be more familiar, it could be "Waar je naar kijkt".
It's still suggest changing that title to something like "What's new", though. Because I'm not actually watching those videos.

Same goes for "Reply" and "Reply to Root", which I'd personally change to "Reply to [whatever the user's name is]" and "Reply to thread".
Oh, and the "edit profile" page is still in English.