2.Social

1. Surface experiences are inherently multi-person and therefore more social by nature
2. in standard GUIs, Social barriers occurs because of the input and output methods
3. Surface accepts multi- person input,so multiple users can gather around one Microsoft Surface Unit

1.Seamless

1. Require users to be Mentally and emotionally immersed so they fearlessly commit to new experiences 
2. The suspension of disbelief refers to a person's willingness to accept as something as true
3.Achieve suspension of disbelief by making objects behave the same way as object in the real world

These are about the Main Points of Seamless

UX Guidelines and principals

NUI:-  UX Guidelines and principals

1. Seamless
2. Social
3. Spatial
4. Super Realism
5. Contextual Environments
6. Scaffolding
7. Performance Aesthetics
8. Direct Manipulation

Evolution of user interfaces

CLI :- Command Line Interface { Command Prompt or windows Power shell User Interfaces}
GUI:- Graphical User Interfaces { Windows Applications Such as Microsoft Word  etc .... }
NUI :- Natural User Interfaces { The New Methods which Has No Special Input Devices Such as Keyboard/Mouse
Eg:- MicroSoft Surface }

NUI

Natural User Interface

What Is NUI ?

NUI is nothing but Natural User Interface. 

The word natural is used because most computer interfaces use artificial control devices whose operation has to be learned. A NUI relies on a user being able to carry out relatively natural motions, movements or gestures that they quickly discover control the computer application or manipulate the on-screen content. The most descriptive identifier of a NUI is the lack of a physical keyboard and/or mouse.