Using strSubject

I would define a new variable at the bottom of the common.asp file say

dim strMortiKeywords

(to make sure its 'unique')

Then set your 'default' keywords under it like so

dim strMortiKeywords strMortiKeywords = "my+keywords+for+advert"

Then in the forum_posts.asp  file set the bottom of the ASP section, before the HTML starts this:

strMortiKeywords = strSubject

To get the + in, you can either use

strMortiKeywords = Server.URLEncode(strSubject)

or

strMortiKeywords = Replace(strSubject," ", "+")

The Replace method will only replace spaces with the + sign, if (as i suspect) you need it for a URL, then the URL Encode method would be better as it'll make sure the subject is "URL Friendly"

Then pass it to your advert, as you are already with strSubject

You can then set your custom variable on any other pages with say forum titles on forum pages or anything else if you wished.