The general public in America are becoming aware of Wlad by way of Hayden Panettiere. That will make a big difference for him, particuarly if he markets it. Here's an example of the kind of thing that is all over the entertainment media outlets and are read by millions and millions. http://www.people.com/people/article/0,,20697562,00.html?xid=rss-topheadlines
For sure they have fans everywhere, they are HW champions love their style or not they rule the division, so off course they have fans everywhere.
I believe that Wlad has a relatively big fan base among american BOXING FANS, but he is probably not that known to the general public.
Among Americans of Eastern Euro descent, he's a superstar. I know quite a few Russians who go to my school that love some Klitschko and stream all his fights in the library.