The US Department of Labor mandates which posters must be displayed. Visit the US Dept of Labors website for specific information regarding your state.
The posters must be hung,or you may face fines. You canorder your posters at www.laborlawcenter.com.
The state of Florida requires a number of posters to be posted in plain sight at the workplace. These posters include topics on federal labor laws and state labor laws. Posters on no smoking and forklift use are optional but also common in the workplace.
Workplace posters need to be in an area seen by all. Most employers post the signs in the cafeteria or breakroom.
Go here and click any of the "download" links on the page to get a PDF of the described poster: http://egov.oregon.gov/BOLI/CRD/C_Postings.shtml
Employers in Texas may be required to post several different posters in their workplace. These posters can be purchased in a frame or laminated. They may also be downloaded for free so that you can mount them however you like. Check out: http://www.twc.state.tx.us/ui/lablaw/posters.html for the posters you may need.
You can order law posters online. You must have the posters hung in the workplace to avoid fines and penalties.
This site lets you tailor a search for your state. http://www.laborlawposter.us/ You can select posters and have them delivered.
Ohio has several posters that must be posted the workplace in 2010. Laborlawposters-online.com sells these posters, for an additional charge you can get them laminated. Check out: http://www.laborlawposters-online.com/Ohio-Labor-Law-Poster?gclid=CNjItu7ehqACFSYbagodgzAcmw for all of the info you need.
The online company Tasco-safety sells workplace safety posters. People can also download the OSHA (Occupational Safety and Health Administration) poster for their office from the OSHA website.
Here are all Arizona posters available in PDF form. Which ones you must have posted on your job site depends on the nature of your business. The notices for Arizona workplace posters is no discrimination, don't get expose to dangerous liquids, unemployed plan, no smoking, and last but not least the minimum wage act.
Just my opinion, but they probably do somewhat. The most vulnerable workers may not know their workplace rights. These posters are another vector by which they can learn them.