For design, I could see something like this in the upper right where the follow links are:
With more being one of the cool popups with:
follow @user | follow #tag1 | follow #tag2 | follow .domain | + more
Would definitely be less crowded with only one tag, but this would be mainly the same as it is now but with a "more" button. But, I will definitely concede that it would be a waste to implement if it weren't going to be used.
edit: I also completely agree with caelum19. A nice query string structure would be super nice to have, and I think it'd go well with more specific following options.