What is the difference between full HD and HD ready?

What is the difference between full HD and HD ready? Hmm...Even I used to get this question pretty frequently! I got this golden article in a magazine and thought would share it with you guys. It was always a confusion between both as they look similar! Honestly, they are more in terms of a marketing strategy. But still if you wanna know the difference,

Full HD usually means video playback at 1080p,which means 1080 horizontal lines with
progressive scanning. HD ready usually means 720p or 1080i, where ‘i’ stands for interlaced scanning.
In terms of pixels, a line resolution of 1080 should guarantee a video output resolution of 1920 x 1080 (vertical x horizontal pixels). If you know, every screen or frame of a TV broadcast is made up of multiple horizontal lines that form a complete picture or frame.

Interlaced resolutions mean that only every alternate line of the video is being shown in one single frame at one time. This means only half the resolution of 1920 x 1080 will be on the screen at one time; if you were to number them all you would first see all the odd-numbered lines and then all the even-numbered ones. They are switched so rapidly that the eye constructs a single continuous image, but effectively you are watching your videos play at reduced quality.
Full HD (1080p) includes the lower specified resolutions, but also adds the ability to display all 1080 lines for each frame, instead of just alternating halves. The entire screen area of 1920 x 1080 pixels will be active at all times.

Videos playing at 1080p will have more detail and better overall quality."HD ready" displays are therefore cheaper than Full HD, and are usually the only choice with smaller sized panels. In any case, these displays are usually not used to their full potential in India as HD TV broadcasts are unavailable, and Blu-Ray discs are still quite expensive.

Ref: Chip

Check out the following link for an in-depth explanation of HD:
http://en.wikipedia.org/wiki/High-definition_television