I have a question about post suffixes like "DIY project" and "Product Review". Can people add these to their own threads? Or does some staff member add them when he thinks the thread is good enough to earn one?

Moderators apply them.

I usually add something in the Topic title about it being an review for example but from what Nathan wrote and confirmed as I assumed the " official " Tags are done by the moderators.

If write something in my Topic titles as I assume this may make flagging them easier for the moderators ? or at least this is my intention but I wonder if this ends up being redundant. :?:

Thanks for the explanation!

Moderators must read every post to do their job correctly. The clear topic titles help, but we should be reading the posts anyway. :)