Hunters are people who are focused in their search. They are deliberately looking for your service or product. They might want to buy now, in the future or may just be gathering information to buy elsewhere. To attract them, you need to be listed in all of the search engines. To keep them, you need to provide a compelling reason why they should buy from you rather than from someone else.
Browsers are more casual.
They are the window shoppers of the Internet. They probably approach your site via a hyperlink from another site, so techniques such as reciprocal links, banner ads and web rings attract them. To keep them, you need to provide interesting, fun content and enough of a reason to hang around to absorb your sales pitch.