I have already posted a blog pertaining to Un-licensed contractors but here I go again.
The popular on-line marketplace "Craigslist" is a growing source for consumers & contractors alike. Advertising is basically free & there are a multitude of services & products that are being bought sold & bartered.
 After talking with clients & fellow contractors it is evident that a lot of business is being conducted through "Craigslist & less through traditional sources like yellow pages
& newspaper advertising.
 Why? Well it is much easier & less tedious then thumbing through the bulky phone book or trying to read the fine print in newspaper ads. Not to mention you can just type in a service your looking for & literally several hundred ad's will pop up for you to choose from.
 While this is great for both Contractors & Consumers, it is becoming a buyer beware scenario. 
After reading through many of the "Skilled Trades" services offered by companies, I noticed that most of these companies who claim to be professional & in business for many years boldly say they are UNLICENSED!
I wonder if they know that contracting without being Registered with the Arizona Registrar of Contractors is Illegal
in the State of Az ?
There are many contractors whom are Licensed & offer legitimate & quality services on the "Craigslist". 
However, don't assume because a contractor is licensed that they are in good standing with the AZ ROC.
All licensed contractors are required to post thier ROC # on all of thier advertising.
It is easy to go on-line to check the status of a licensed contractor by checking the contractors License # with the Az ROC by going here.   http://www.azroc.gov/clsc/AZROCLicenseQuery

And to be safe, never ever use an Un-Licensed contractor!
They will probably be cheaper, but that is because they are not paying an annual contractors license & bonding fee or liability insurance to protect your property.