I used to see some Googles ads under a new thread, just like to know is this ads actually placed by DP forum automatically or placed by the user? If by user, how to do that? Sorry if I asked a stupid question.
It's placed by dp but you can gain some revenue from it if you put your adsense id in your profile. Check out the faq about revenue sharing : http://forums.digitalpoint.com/faq.php?faq=dp_faq#faq_revenue_sharing
Try to see also the posts on Revenue Sharing... It seems that it is safer to avoid that, and don't excpect to make any decent amount of money anyway.
I guess its mostly for fun... how many of us clicks these ads anyway? Even if users could place their own ads... i bet it would be disallowed.