Insert userid into a link within a post automatically?

[afullcup]

Is there a way to insert the userid of a member viewing a post into a link within the post?

For instance, in an affiliate link, to create tracking... I have tried:

<a href="www.affiliatelink.com&tracking=$vbulletin->userinfo['usergroupid']'">

and have tried several others like $bbuserinfo[userid] - but none of those work to insert the actual userid - I just get the text in the URL.

Is there anything that will allow me to pull that into the link for each view? can I do additional html coding around that link to string together a link to use inside the link tag?

Hope that makes sense! :)

Thanks!