1)Try to find out what type of website owners would see the most benefit (large, small, ecommerce, blogs, Wordpress?) and target them heavily. Get it to as concise a group as you possible can, then make it yours. Then find your next niche, repeat. each niche will take a while to work through though, so do your homework?
2) Try to find the individuals most likely to adopt and try the product quickly. Often this is not the same group as #1, though it may be. Follow similar rules as in #1 and try to take hold of a smaller group of user rather than just going after the huge number "website owners" out there. Web savvy folks are, by nature, early adopters, but with your product, some will always adopt faster than others. Find them.
EDIT- Also, if you can include a more detailed description, or a link, that would help the HN community wrap its head around your tool