Two wildly-unrelated items today got me thinking about audience building for applications. An Android app developer feels like he was robbed by Amazon – his app was featured for free and moved 100,000 units. But that didn’t lead to increased sales afterwards. TechCrunch remembers Amazon promising to pay 20 percent of list price for the giveaways. Amazon certainly paid Interscope the usual wholesale price for the Lady Gaga album it sold for 99 cents, but that was to aid Amazon’s own marketing. The complete reverse of Amazon’s approach is EA Sports’ subscription initiative. Hardcore fans can pay $25 a year upfront to get the hottest titles three days early. But they can only play them for those three days; then they have to buy them. That will be one to watch – I think it just might work for big fans, but not the masses. Gaga’s sales didn’t hold up, but she got PR benefits and dominated the news. If you’re going to try to build an audience on the cheap, you better help that audience spread the word virally, and follow up aggressively with more traditional marketing, not to mention upgrades.