The main site is currently designed for use solely on a non-mobile browser, so .com is a natural choice. We also have a mobile site specific for testing and it is called TA-DA.
We have a complete list of the properties we support available on the site. You can see it here, http://deviceatlas.com/properties.
We are constantly improving DeviceAtlas and adding new properties, we are interested to hear what properties you need and how you would use them, we invite you to discuss with us in our public forum, or send us an e-mail if you need to discuss this privately.
Every browser, when visiting a website, sends a number of strings known as "HTTP request headers". The user-agent string is one of these headers and is known as one of the best identifiers to recognize a device. DeviceAtlas uses this as part of its detection system.
We have a forum where we have open discussion about DeviceAtlas features, provide support and also provide information about upcoming updates and changes.
At present there are approximately 3900 devices, for which we provide 70 properties. New properties are added based on market inputs, and the number of devices is growing steadily. You can see a list of all the properties and their descriptions here: http://deviceatlas.com/properties