Not all devices support O-Auth, so using the Twitter authentication becomes difficult. Tinamous addresses this problem by allowing the use of HTTP Basic or API Key style authentication for your 'Things'.
The API is the cornerstone of Tinamous. You can read/post status messages, add/read measurements, as well as raise and handle alerts.
You can also connect using MQTT which supports publishing and subscriptions for status posts, measurements and alerts.
By default, when you create a Tinamous account, it's private. You can add and invite people and your 'Things' to it, but unless you make the account public, only the users you have invited are able to see the posts in your area. You even get your own Tinamous sub-domain (e.g. StevesHome.Tinamous.com) (hurry, get yours before the good ones are all gone!)
Twitter is indeed a good solution for one to may human communication; however, it's far from ideal and not really designed for connected devices and private social networking.
Tinamous is designed for the integration of status posts, alerts and sensor measurements using simple, open connectivity solutions.