This can be tricky.
In my recent government work, recruiting was not allowed: the closest we could get was to happen to notify someone that a position had been posted. Hiring was by the best of the people who actually applied for the position, excluding only those who failed mandatory qualifications.
The hiring procedures were pretty serious stuff, having been developed in response to a number of lawsuits over the years, including multiple government losses at the Supreme Court of Canada level.
That said: one I had someone's application in-hand, it was considered entirely fair for me to examine their public postings with regards to "competencies" that had been listed on the job posting. For example if part of the job included communicating with users, then it was fair to examine how well the applicant explains things. Which is a different matter than how technically skilled a person is, with ability to explain well being rather less common than raw technical skill.
That having been said about recruiting in that environment:
It is a very human tendency to prefer to deal with people one knows, even if only through postings. A person with known skills and known types of reactions can be worked with. There might well (it is statistically likely) be other people with better or broader skills, but an unknown individual is also a risk -- until you know them, you worry that they might "jump the couch".
For example one time that I was looking around to see whom might be available, I discovered that one person I checked out was hostile towards individuals of a certain nationality; that was not acceptable our environment, especially as we had some people of that nationality working for us.
Preferring to work with people one knows is also a disadvantage, to the extent that it interferes with taking the opportunity to meet someone with good skills that one did not happen to have met. There was a period during which we could hire students: some of the students that we hired without having met before the hiring process turned out to be wonderful -- and some of the students we knew something about before-hand turned out to be not so great. Unfortunately, one only has limited resources, so one tends to select from the best one knows.
It has long been my personal opinion that the socialization of programming has changed over the years, that the days of the lone programmer in a basement are mostly gone, and that (except perhaps in some theory work) to really work effectively these days pretty much requires comfort and familiarity with electronic resources such as this forum (or even Facebook). A person searching online for information about how to do something in MATLAB is going to find that there are not many active resources on the topic (though lots of web pages showing how to do specific things.) These days, I expect people interested in a subject to look around for electronic resources, and if they don't, then it gives me pause to wonder if they are the right person.
I have noted that there are some undergrads who offer assistance here. The answers they give are sometimes incorrect or incomplete. But what I look at is not whether they are wrong on any one response, but rather I look at how they are trying and how well they are learning from their mistakes. Facts are learnable in time; the habit of effort to continual improvement is not something that can be taught.
On the other half of K E's question, of searching for employment or contracts here:
Mathworks does not wish this to be a "job wanted" board, and does not wish people to advertise their services here. Some advertisements of services have been removed already. The only area in which one can post one's availability is in one's profile.
I understand Mathwork's position on this matter, but for selfish reasons I do sometimes wish it were otherwise, so that I could advertise myself.