The problem with TechCrucnh stories is that they never get the effing analysis right, so lets go to the source instead. In this case its the code author of Car Locator, A AD2 winner. If you view the full blog of posts, you see symptoms of advertising in that after the AD2 win the uptake in sales starts occurring. But we have to know why.
First int, Edward Kim provides a free version of Car Locator and the conversion rate to paid is about 9%. The only advertising he has at the moment was 3rd place AD2 winer and Android Market featuring his application. In other words his advertising effort is not there yet or put another way only half complete.
Let me explain. On the iPhone side an app developer will make a full version freely accessible to reviewers by using a timer to time out the application use past a few days. That way you lower the barrier to having all mobile application reviewers review the application and write their application review for the blog reviewing it.
Thus, the take away points seem to be use the free application to lower the barriers to having the application reviewed and featured by internet media and that Android devices deployed on Verizon helped.