I see that almost all of the people of StackOverflow leave their About Me area without using it as a sales page, to showoff their skills, projects or anything that could get them big business. Why do they do so? Maybe because the questions and answers speak for them?
Maybe because the questions and answers speak for them?
Pretty much. I have my current job because my employer found me on the top (weekly) page of Stack Overflow, contacted me, offered a far better job than the one I was in, and the rest is history.
Besides, what else would we put up there? What exactly are we developers usually "selling" besides our skills and time?
I'm not a consultant for hire right now. That's kind of the idea.
Some who are, do. This ultimately comes down to "why do people answer for free," though.
Some even promote stuff that others might find useful. Such as... themselves. Of course, the best way to prove it is to answer a bunch of questions really well, so...
Many don't because they don't have products to sell. That, and many programmers just aren't that entrepreneurial.
The ones that are entrepreneurial are rich. Think Bill Gates and Mark Zuckerberg. Think Jeff Atwood and Joel Spolsky. (Those last two have pulled a coup like none I've ever witnessed.)
Not every profession has this kind of mindset. I sense it's a contributing factor to the fact that the Personal Finance and Money Stack Exchange has been in public beta for over 1,000 days. There just aren't that many people knowledgeable about that subject who see the benefit to their careers, or their bottom line, by building someone else's web empire. They build their own empires.
Some do it for the same reason they do it here -- because they like to help. But there's a miniscule direct payback for their work. The top-ranking user over there has gotten less than one profile view for each question he's answered.
If people want "conversions" for a product, there are far better places to do that than their profile page on the SE network.
A number of people are here on SE sites to "advertise" themselves. Most of them just aren't obvious about it.
There are plenty of sites, and plenty of ways to showcase your talents, mainly by writing good answers (or questions). Anyone who wanted to "advertise" could sent a link to a prospective client, or hiring executive.
For a variety of reasons, most professionals don't want to make it too obvious that they are looking for business or a new job, either on this site or elsewhere. It's one thing to have a set of answers or questions "in stock," and quite another to go flaunting this, especially on their About Me Section. Many people have strategies that are quite subtle, and don't want to be seen "making a move," until they are actually ready to make a move.