Supervisors can...
(For more information about the Super Powers of the Supervisors, see the Related question.)
A regular contributor is someone who does not have Supervisor status, or CA status.
There's no way for a Supervisor to know unless the contributor either deletes the warning message or responds to the message on the Supervisor's talk page.
There is no "best" supervisor. All supervisors are considered the "best" because they contribute more to the site than a regular contributor. Each supervisor is the "best" in their own special way, be it in a single category, or organizing categories of a certain category.
Yes, all users, regardless if they're a supervisor or not, will have a contributor level badge. This could be a contributor, bronze, silver, gold, platinum, double platinum, or ruby level badge.
Like most of our records, supervisor HisPowr4U was the first...along with being the first Ruby contributor. Who knows what heights this supervisor can achieve?
Self-promotion is allowed on a contributor's Profile page but never in an answer. Most likely the contributor is a robot. Most robots will be blocked from the site by a Supervisor. If you are a contributor, you should report your finding to a Supervisor, who will deal with it accordingly. However, if it is a normal contributor, the user will be warned by a Supervisor to stop advertising in answers. If the user does not heed the warning, their account will be suspended. WikiAnswers is a Q&A site, and it not to be used for advertising.
The same way a regular contributor would become a supervisor. The most common way is to become an SPA (Special Project Assistant) and spend time doing tasks to prove if you are worthy of becoming a supervisor. To view more information, view the link below.
Yes, they have the ability to un-block a user.
Supervisors on WikiAnswers are just regular users who have been very active on the WikiAnswers community. You can become a supervisor just by doing your best to help out on WikiAnswers in any way you can. If an existing supervisor notices how good a job you are doing, he may recommend to a WikiAnswers administrator that you be made a supervisor.
If you believe that your answer is correct, but a contributor keeps spamming/changing the answer, let a supervisor know. They may be able to protect the question, and/or block the contributor.
Contributor badges are earned by simply answering questions, editing answers etc. Supervisor badges are given (by a higher supervisor) when someone is nominated as a category supervisor.
You can technically get all the badges, but you can't have them all at the same time.For example...You can't have the Premier Answerer and Supervisor/Community Assistant badges at the same time.You can't have the regular (first) Contributor badge and the Supervisor/Community Assistant badge at the same time.