Affiliate links coming to my site

Hi folks,

For example I run a site named x.com,
and I make a partner program so my visitors can gain points/comission or something else through my site.
So every user in my site receives a link:

x.com/refr.php?cid=yyy

where yyy is his user ID.

this script refr.php sets a cookie and then redirects to my main site x.com. Should I use 301 header in refr.php script that it is moved permanently? And one more question - if my users start inserting too much links on their sites, blogs, forums etc, can I be penalized by Google? Or when 100 of my partners place their partner link on their website will my main site increase a lot it's google ranking?

Thanks folks.

I don't think you are going about this the right way. If I understand correctly you can only link to /refr.php?cid=yyy. But what if they want to link to deeper pages on your site? Affiliate purchases work best if the clicks are less. Being redirected to your homepage, forces more clicks on the user and even forces him/her to find the product/service/information they were looking for, instead of being linked directly to it.

I would make it possible to affiliate connect all your pages, not your homepage alone.

x.com/products/14inch-blue-widgets/?cid=xxx

and use canonicalisation meta of

x.com/products/14inch-blue-widgets/

to keep the juice. Or redirect to that url and strip the cid var alltogether.

Your pages need a simple "if isset cid then store cookie and redirect to page they were linked on".