This invention provides a primary uniform heater in the natural temperature preserving main body and it is conducted to a room needed to be heated, where the temperature can disperse openly; the temperature is transferred by the heat-conductive fluid by a main pump, or further by a shunt pump; that is, fresh air enters into the primary uniform air-heater through an open filtered inlet, and enter the primay uniform heater of the natural temperature preserving main body and then it is pumped through a transfering tube to a detector in the room needed to be heated. If the conductive tube is long enough to be buried in the natural temperature preserving main body, the primary uniform heater can be omitted and the tube is made of good conductive material's to actuate the function of a primary uniform heating power; a primary filter, such as active carbon filter, tester for harmful gas, and air fresher, can be attached to the inlet and the outlet of the fresh air.
Enabling a first user to preview content as it would be seen by a second user, if the second user had a selected user relationship with the first user. The selected user relationship may include a relationship degree, a relationship category, a relationship rating, and/or other form of relationship. In one embodiment, a user interface enables the first user to assign user relationships to portions of content and to other users. The first user selects a user relationship, which is used to access those portions of content that are associated with the first user and assigned the selected user relationship. The corresponding portions of content are used to generate a preview display for the first user, illustrating the portions of content that would be accessible to other users assigned the same user relationship or assigned a closer user relationship. Preview may be generated by a server or a local client.