these spammers always come in and are able to make thier subject lines longer than the limit. How are they doing this? I don't see any abnormal code in the mark-up. Look at the top posting spammer post with really abnormal subject length. http://i.imgur.com/iBk2d.png

Guessing your url.
It appears first you have a old version 6.5.4
There have been many bug fixes since then.

Also it appears you have html enabled for posters.
Another exploit avenue.

I know so how are they doing this?

Was there even a topic length in v6.5.x?

BTW, you already have a topic on this here from June 11, 2011.

I know still no answer. There is a topic length.

Then first item would be is to edit the topic as a admin and post what is in the subject here.

I want to learn how the spammers do it. Not just fix it.

With what you have posted on two different topics.
The issue is a old version of ubb.
Just guessing since html is enabled someone posted a topic subject with html using less than the characters than the limit. Big security risk enabling html to all.

You will need to provide more details on the posted topic for anyone to help more.
Such as mentioned before. What was entered in the actual post.
Not from a view source.
I would suggest you contact the admin of the site and have them visit this post for assistance.

FYI,
I don't think anyone here is going to help you learn how to exploit a site.
Assistance/Help,yes!