Whatever forum you use, you'll have to examine the PHP scripting and
locate the correct template file that handles displaying the posts. That's
why we're asking you about what forum you're using. Each forum is different,
and we can't provide any script examples without know which forum you're
using.
Also, we have no idea where your ads are coming from. Do you have a list
of ads in another database? Are the ads randomly extracted from a remote
site? Are the ads inserted using a Javascripting method?
I could answer your question like this with the information you provided:
Put this code in your forum where the posts are displayed:
PHP Code:
$count++;
if($count < 4){
echo "Buy a new car! <a href='www.ford.com'>Ford Cars</a>";
}
There you go, that's how you do it.
See what I mean?
How is that going to help you?