Checkout on different domain

[PrintingForLess.com]

Is it a bad SEO move to have a your checkout process on a separate domain instead of the main domain for a ecommerce site. There is no real content on the checkout pages and they are completely new pages that are not indexed in the search engines. Do to the backend architecture it is impossibe for us to have them on the same domain.

An example is this page: http://www.printingforless.com/2/Brochure-Printing.html

One option we've discussed to not pass page rank on to the checkout domain by iFraming all of the links to the checkout domain.

We could also move the checkout process to a subdomain instead of a new domain.

Please ignore the concerns with visitors security and conversion rate.  Thanks!

[icecarats]

In my opinion there isn't really any downside to this from a Google perspective; as you said, they shouldn't even be indexed anyway. Many many vendors out there have their charge/fulfillment go straight to PayPal for example, and don't even host any checkout specific code (other than cart-building, account creation, etc.) on their site at all.

There's also the case where multiple microsites will all use the same checkout on another domain, used to centralize checkouts. As far as I know these sites aren't punished either, and it definitely saves money on the secure certificates.

There is however, another angle to consider, and that is the human angle. Some people (who aren't savvy about ecommerce) might be alarmed that their secure checkout is occurring on a different domain than the one they've been browsing on. This is a 'security/conversaion' rate issue though, so you may already know of it.

In my opinion I would leave it alone and not bother with the iframe tricks and so on. A subdomain might be more reassuring to the user (e.g. secure.printingofrless.com instead printingforless1.com) but I honestly can't see why the current setup would have Google implications, as long as your SSL/non-SSL pages are separate and canonicalized properly.