#7 on the Participation Requirements documents says that Amazon will not pay commissions on links from mobile sites to Amazon.
I queried their tech folks there about how that specifically would be a restriction on mobile sites.
Basically, in summary - and you can PM me if you want the full quoted email reply but I don't want to post the exact whole thing here - you can link to Amazon from a site that is not designed as a mobile-specific site.
In other words, you can link from a site that happens to look OK when visited by a mobile device, and you can use CSS media queries to make said regular site look OK on mobile devices.
BUT, you cannot redirect your main review site to a mobile version through a mobile redirect and have links to Amazon on the mobile version - say on a sub-domain or .mobi or anything like that.
So direct mobile sites showing up in search and being viewed on a mobile device or tablet can't link to Amazon and get paid commissions, and if a mobile device visits your "desktop-type" main site and redirects to a mobile site, you can't link from that site to Amazon and receive commissions.
Basically, one site with a flexible design is OK, but a separate site for phones and tablets, not OK.
Just trying to save anyone from doing the work to capitalize on mobile and mobile search only to find out that Amazon won't be paying you for those mobile site links.