Your best bet is to locate websites that focus on a similar subject matter to your hubs. As an example, I wrote photoshop tutorials, so I went to art websites that had user-submitted tutorial sections and submitted mine as offsite tutorials. The traffic was slow to catch on, but it's been fairly steady ever since. Similarly, if you post a lot on message boards, then create a signature for yourself that includes a link to your hubpage profile. That way, it's tagged on all your posts as a way for people to find you elsewhere, but it isn't dominating whatever subject you're talking about. Places like pinterest, facebook, twitter and reddit are also sites that you can link to your newest hub without getting accused of spamming.