This is an example niche. Lets say my niche is Runescape Accounts and I am trying to get it ranked on google and lets say this is my url RunescapeMemberships.com I am trying to get Accounts ranked but Memberships is the domain. Will that effect it ALOT? I know it will have some effect. But say they search for Runescape Memberships mine will still show up although it is accounts right?