The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Industrial Thinking:
Counterpoint Trend Mobile provides Real-time remote access to your Production data directly on your iPhone. The intuitive user interface enables you to browse, Search and Trend tags from any of your configured Data Historian(s). Tilt for full screen, pinch zoom, shake to return. Download the app now and try it with one of our preconfigured historians. Supported Data Historian interfaces include most of the Industry Standard Historians, such as AspenTech Infoplus.21, OSI Pi, OPC DA and HDA, Honeywell PHD and VSystem. In order to use in your production environment you will need to have a licensed Counterpoint Historian Interface.