Originally Posted by realitycheck69
mp3 takes up less space than aac
Those numbers reflect how many bits per second are "played". So a 320kbps song that is 3 minutes long is 7.2MB. That same song at 256kbps is 5.76MB. Those are CBR encodings and rough estimates for VBR which tries to average out highs and lows to obtain the desired bit rate.
While the AAC format (based off Apple's QuickTime container format) does have a bit more overhead than MP3, it is negligible when compared to the actual song data. The AAC file format also offers a lot more metadata and different types of data to be stored, so it may simply be a case of the AAC file containing more detailed information.
I'd also like to say, that this will in no way have any affect on Apple or iTunes. This is Google's attempt to cut into Amazon's share, which is the content store most used on Android devices. Also, Google has not had any luck in getting their user base to actually pay for much of anything (thanks to Google's MO of handing out everything for free), I don't think this new service is going to help much either. Google is getting into every market that is associated with personal information, which includes music tastes, in order to further their user profiling - the more detailed information they have on you, the more valuable you are to them as a commodity.
A couple of quotes from Eric Schmidt...
"We know where you are. We know where you’ve been. We can more or less know what you’re thinking about.”
“I ACTUALLY think most people don’t want Google to answer their questions, they want Google to tell them what they should be doing next."