Generally it's considered a faux pas (and downvoted) to advertise on other users' Show HN.
HN doesn't have an anti-commercial position like other forums, but competition on Show HNs is heavily frowned upon, since we're supposed to be celebrating the user's initiative and effort, not just look at a product.
Best way to do this is wait a few weeks then post your own service :) People will then automatically begin discussing yours versus another one that was posted recently, etc.
HN doesn't have an anti-commercial position like other forums, but competition on Show HNs is heavily frowned upon, since we're supposed to be celebrating the user's initiative and effort, not just look at a product.