There is no limit as to how many trust points a person can earn on WikiAnswers. Currently, the highest number of trust points held by a person on this site is well over 8,000.
There is no maximum amount of trust points one can have on WikiAnswers. At present, the highest amount so far is well over 8,000.(For a list of users with the most trust points, see the Related question)
Trust points do not entirely help you get hired to work for WikiAnswers, since actually getting paid to work for WikiAnswers is different from the amount of trust points you received online.
The numbers beside the usernames are Trust Points. Trust Points are points given by other contributors who think a contributor has done an outstanding job on WikiAnswers. The amount of points is the amount of people who trust you and your contributions. There should be a 'recommend' button by your name if you made the last edit in an answer. You can recommend yourself once. To advance your Trust Points, just make high-quality answers and/or contributions to WikiAnswers and someone is bound to trust you.
Your total WikiAnswers contribution points are calculated as the sum of all of the contribution points you have earned. These include first answers, edits, organizational actions, questions asked, and community contributions. All of these points come under the heading of "Contributions" in your WikiAnswers profile. Trust points are slightly different. Contributors do not directly earn these points through their contributions; they are awarded trust points by other WikiAnswers users. Therefore, trust points are not counted as contributions, and do not add to the contribution points total in a WikiAnswers profile.
The rating next to each username is the amount of trust points they have. That is the number of times they have been recommended by another contributor.
No. You become a Bronze Contributor after 500 contributions to the site.
Many have.
Currently, the WikiAnswers system of trust points hasn't changed - you can only add trust points, and you can only recommend from a question the user has answered by going to the contributors tab and clicking "recommend".
No, you are not able to hide your trust points from other users.
No, neither giving nor receiving trust points count as contributions.
That is more up to your decision. If you look at the username or ID that answers the question, it would show the amount of trust points (ID's do not have trust points, so trusting them is more of a last resort). When you look at the username, the higher the number is of trust points, the more reliable the answer is.
Currently, there is no badge for accumulating 50 trust points on WikiAnswers. The badges are awarded for the following: 500, 1,000, 2000, and 3000 trust points.