Today Apple anounced the release of its 40th iPod model, a new Ipod shuffle model that has 4GB of capacity with a new ‘VoiceOver’ feature. The larger capacity, new feature, and lower price are all hallmarks of how Apple has evolved its iPod line during the past eight years. The following graphic displays all the 40 iPods Apple has released, categorized by their main features or product families. Each bubble indicates an individual iPod model, and the size of the bubble denoting the capacity of each model. Since the iPhone is considered to be a distinct product line none of those models are included here.

New models with premium features have regularly been introduced at higher price points. The fourth generation iPod “Photo” with a 60 GB capacity is the first example of this. A more recent example is the Ipod Touch which offered internet browsing and gaming capabilities, also at a premium price point. While Apple has innovated in its iPod features it has also gradually lowered the prices while increasing the capacity of existing iPod lines. This two pronged approach of continual innovation and increased value has garnered Apple continual sales growth, which will surpass a total of $200 million this year.

It is interesting to speculate how Apple will continue this strategy during the next five years, and which possible new iPod features it will come up with.