Are you referring to hub pages specifically or to websites in general?
Article directories (drafting aricles, placing your link - perhaps even to your hubpage - within the author's box) are a great resource. Try ezines.com or google "article directories" to find a more comprehensive list.
There are services like Rapid Free Traffic (you can see a review I did of it here: http://www.honestibizreviews.com/rapid-free-traffi... that can automate the process. It's what I use, but there are other products out there that are comparable.
Commenting in forums (without sounding spammy) also works.
Hope this helps.