I have edited the brief to add:
Edit #2: I'm adding this to the top, as a lot of people are missing it further down. The app is just released a few days ago, and the existing "W" logo was only a temporary logo that was needed during development. Please don't base your submissions on the current logo.

I'm going to repeat again, because people are still submitting logos based on the letter 'W', and I hate to see people wasting their time --- the current 'W' logo used for the app was only temporary. The app was released three or four days ago. I needed a logo to release the app, as someone who isn't a designer I just spent five minutes putting anything together until a better logo could be made, which is the process we're all going through now. The 'W' has no meaning -- it is the equivalent of Gmail's first letter of the username in lieu of a contact photograph.