I have links to my profile and my hubs on my websites and my two Yahoo groups. I also have links all over facebook and Twitter. In fact, hubpages puts them there for me. I'm sure you saw that option when you published a hub. You can put links on any site you control content on.
Hubpages has restrictions on what links you can embed in the hubs or in answers to questions because hubpages controls the content to prevent unauthorized advertising or conflicts with affiliates. You need to read the hubpages writer's info for that.