HarmonyTweets says that its purpose is to "plug you in to innovation and inspiration updates from charitable organizations, industry leaders like Toyota, and sustainability-minded individuals". In reality it is a marketing tool for the Toyota Prius that uses Google Maps to show the latest Tweets about the car.
As a marketing tool it isn't quite in the league of the Zappos Map or the #ukhols map. Online retailer Zappos used Google Maps to show the latest purchases from the store live on a Google Map. The Zappos Map animated in real-time between the latest purchases to create a dynamic map.
The #ukhols map from Vodafone was a Google Maps mashup that let people in the UK Tweet where they were going on holiday and then see their trip plotted on Google Maps.
Both the Zappos and #ukhols map were dynamic, interactive and exciting to use. Unfortunately for Toyota the HarmonyTweets map lacks this dynamism.
The map shows the latest Tweets about the Prius. For the user there doesn't seem much incentive to click on the various map markers to read the gushing messages about the car. Which I guess is why HarmonyTweets has tacked on Tweets about 'giving' (Tweets about charity) and 'inspiration' (Tweets about sustainability).
Beyond trying to create a positive perception about the car it is hard to see why these Tweets are also on the map. Overall the map comes across as a pretty cynical marketing ploy. The least they could have done is animate between the map markers to make the map more visually appealing.