Amie Street announced Wednesday that it's been acquired  by Amazon for an undisclosed amount. The news comes three years after the giant online retailer originally invested in the startup's first funding round in August of 2007.

Amie Street, which raised its last round of funding last year,  is unique among music download sites because of the way the value of the songs are determined. Unlike other services that charge a flat rate, like Apple's iTunes, or subscription-based models, like Napsterl, Amie Street takes a social approach, allowing users to bid up the price of the songs. The more users that purchase the song, the higher the price goes. Rates typically range from $.50 to $1.

Amazon has not stated whether or not it will keep this business model, which has prompted some bloggers to speculate that this is merely a traffic buy to help Amazon garner a larger shard of the digital downloads market. Some 28% of Amie Street's visits come via search engine, according to according to Alexa. This leaves the possibility of a large and loyal recurring user base, This base may become important to Amazon once Google launches its much talked about music service in December.

The site will shutter its doors on September 22. Users will need to have all of their music downloaded by this date, or lose the opportunity. Users will not have their current balances carried over to Amazon, though they will receive a digital coupon for $5 that expires in December of this year.
 
The founders of Amie Street have decided to focus their efforts on Songza, a custom radio station site similar to Pandora, only with a strong social media aspect.

Neither Amie Street nor Amazon were avaliable for immediate comment.

(Image source: apcmag.com)