Unless the number you give is significantly higher than any of your potential employers are ever going to offer you, you are shortchanging yourself by giving that number--it means that you have now foreclosed potential higher offers that otherwise might have come your way. That is the basis of the advice given in the article.

I get what you're saying about knowing what you're worth, but that in itself doesn't give you very much help in knowing what potential offers might come your way. Unless you have detailed inside information about all of your potential employers (hint: if you do, you should already be leveraging that information to get a job offer without having to go through all the drudgery of interviewing like everyone else), you can't possibly know how the number you give compares to what they could potentially offer you. So you shouldn't give a number at all.

In fact, the more you know what you are worth, the less inclined you should be to give a number instead of just waiting for an actual offer. What knowing what you are worth should do is help you to decide, on your own (i.e, without asking recruiters who have conflicts of interest), which potential employers are worth your time to even look at in the first place. Don't even bother talking to companies that you know can't compensate you enough. But you don't need to, and shouldn't, tell recruiters what your threshold is for "enough". Just tell them company X doesn't look like it would be a good fit. Nuff sed.

> If recruiters are talking to you, they want to place you at the highest comp package they can.

They want to place you at the highest comp package they can as long as it doesn't risk not placing you at all. They never want to walk away altogether. But you might. So your interests and theirs are not quite aligned.