Ask HN: Why or Why not to advertise early-on in a startup?

I've heard that early on advertising can deter your growth in building your user base, can create a bad reputation for you, users don't come to your site for the ads but rather the content etc.

Contrary to that, I've also heard people talk about launching their iPhone apps with ads from the start and were able to promote their user base with no problem. People downloaded their app and used it because they needed/wanted to use the app regardless of what ads might be in there.

From what I've noticed- most iPhone apps that are backed up by capital (VCs, Angels, etc) don't have ads and secret future plans for some kind of revenue model. Other apps that are individually created don't have the luxury of having the same kind of capital and usually have no choice but to sell ads to survive. Is it proven that you can grow a more successful user-base without ads early on?

In your experience, why or why not should you choose to advertise early on in your startup?