If your not trying to scale your business for investors you have a lot of play in unit economics though. There are lots of ways to obtain customer cheap but they usually don't scale and you don't get lots of them. targeted SEO versus PPC, bing and/or targeted ppc campaigns versus google, doorhangers versus direct mail, non-viral social media.
I think the biggest problem with uber for X is the business model usually entails trading margin for streamlining the business by outsourcing the capital/labor intensive parts to others. And it can only work if your the goto place for XYZ over google and everyone else.