"Desi" is a informal name for people of South Asian descent, particularly those of Indian and Pakistani descent. The term is rarely ever used outside the South Asian community, and is not, for the most part, considered derogetory. But it is used in some instances as an adjective to denote when a person or an object is not up to the expected level.

The term originated in Sanskrit, but has part of the vocabulary for major South Asian languages, such as Urdu, Hindi and Punjabi. The literal meaning varies from national to local to pure. Mostly used by those residing in the western world, DESI is often used to ridicule or define ways of life that a lot of South Asians kept despite being away from their roots.

When exactly did the term become as common as it is today is not known, although some argue that it's first major exposure came from a reference in indie hit "American Desi", when a character is referred to as ABCD: American-born Confused DESI.

Of course, for ApnaSpace, this term has a different, all-encompassing, meaning. For us anyone willing to open up, enjoy themselves in a simple accepting online environment, is desi enough to be a member.

External Resources:
Wikipedia: Desi
Urban Dictionary: Desi
Wikipedia: ABCD
UrduSeek: Desi