The Telstra owned Sensis owns what many online developers consider to be the best online mapping data and this means that if you want your site to offer the best mapping interface you’ll need to deal with Telstra. My only concern with this is for those businesses seeking to compete with Telstra’s Trading Post and other businesses. You’re having to support your competitor in order to get close to their capabilities. Sure it’s businesses and maybe I need to get over it. However, that a competitor can present a barrier and risk in such a way is concerning at least. While others are in the mapping space for some reason they don’t offer the quality of the Telstra mapping data.