You can paste HubPages links anywhere. You might want to check with Demand Media and see if they have any restrictions though. (Be careful of them, BTW. They have been known to not pay writers.)
When you paste links to hubs -- on Demand Media properties or anyplace else -- make sure to use a referral tracker. That will allow people to sign up under you and potentially make you money. See http://hubpages.com/faq/#affiliate for more information.