How come some people can legally move to US without a job? (temporary, travel)

[breakaway]

From reading some of the posts in this forum they say you have to have a job. Yet that doesn't seem to always be the case. What are the exceptions?

[Crew Chief]

My wife arrived in the U.S. without a job (We were married in Germany). And, no, nobody threw money, low-interest loans or welfare benefits at her when she arrived...

[Eastern Roamer]

There are different kinds of visas that grant authorization to enter a country. Many people come on tourist visas, there are student visas, too. Some visitors simply don't leave when there visa expires. There are also temporary residency and work permits and visa waiver programs.

Temporary Visitors to the U.S.