As always, voluntary response data are worthless. https://news.ycombinator.com/item?id=5538059 Good luck to all of you looking for higher salaries. I hope you gain the salary you desire, and more knowledge of statistics along the way.
voluntary response data is flawed I agree, but I hesitate to call this worthless. I'd plaster warning signs all over the place alarming people to think through their reasoning and consider all the biases that would have taken place in the poll. (come to think of it, if the poll data incites that kind of skeptical thinking in some of its readers, that in itself might make the endeavor worthwhile)
But what people are really interested in is "is $125k high or low" and this data is useless for answering that question. It is worse than useless because it may lead you to believe something that isn't true and think you have a valid reason for believing it. It's worse to know something that isn't true than to correctly know what you don't know.