Temporary agencies, leasing companies, Day laborers
These are considered temporary work employers, and a person employed by them typically works at one job for a period of time and then is moved on to another. These are all grouped in one category in unemployment hearings. Companies are suppose to notify people when hired that when a job ends they need to report back to the agency for an additional work assignment, and that failure to do so can result in a denial of benefits. The company is supposed to notify you in writing and go over it with you. Some companies just have a sign somewhere in the office that states this, or even worse tiny print on your paycheck or on the back of it they think you will read.
Once you report back for reassignment that is your obligation as far as unemployment goes. If the employer does not have any additional work for you, it is considered being discharged due to lack of work. The good news is that it is pretty hard for the employer to meet all of the requirements for them to win.
In the current economy this type of employment is good for the unemployed because there should be some immediate work to earn some money. Many times from my experience is once someone is employed by a temporary agency it can turn into a regular full time job when the company the employee is at decides to hire them.