Checking Uber's blog with regards to their API launch, I stumbled upon this thing: As others struggle with same day delivery (check ebay now), Uber has an entire workforce on the streets that, if waiting for assignments, just costs money. Ideally, Uber's cars would be driving 24/7 on some customer request. So why not fill in the gaps with delivery? The only flaw I see (if this takes off) could be a car shortage for people who want to actually get a ride. You can get anything from condoms to diapers and envelopes. No cash required, everything is accounted via Uber.