If you mean using AdSense, no. You can affiliate through Amazon and Ebay and even link to your website that promotes affiliate products for other companies. You are not supposed to link directly to an affiliate product though, except for through Amazon and Ebay.
You can also use Kontera, though I've heard it is less of a money-maker than AdSense.
If you are asking if being listed by Google's search engine is the only way:
You can promote your hub on Facebook, Twitter and other social networks and bookmarking sites as well as from your own blogs and comments.