"People will visit once" is a nice problem to have. Realistically, by the time you have nontrivial traction that way, your software will probably be less crappy. Plus, the kind of people who will subject themselves to sites so new they aren't on The Googles have, ahem, unique expectations about product quality.
yes. I have a site that gets enough SEO juice to have 500-1000 uniques a day for the last 8 months...and none of it from the big G. I've done zero marketing...the eyeballs just keep on coming. I think its fine if some of the first eyeballs never come back...but if you stick around long enough and keep iterating, I believe many probably will.
