Recruiters are not my most favorite people in the tech eco-system. They’re the people that will contact you on behalf of some client (the company that pays them) in order to try to find new employees. They typically get paid a fairly hefty sum per employee found and if ever there was a moment when the ‘you are the product’ meme was even remotely true it is when you are dealing with a recruiter. As with all products, you have a price and price matters, in fact it matters a lot.
Typically they will ask you a bunch of questions in order to figure out if you are suitable for the task at hand and a bunch of questions that have to do with the budget they’ve been given to see if they are going to be in the ball-park and to make the future salary negotiations easier for themselves and their employer.
The key question is ‘How much are you currently earning?’.
Note that you are absolutely not under any obligation to answer this question! That’s your private information and if you pass this little bit of information to the recruiter you’re doing several things:
you have just blown your negotiation position out of the water
you have passed information from your current employer to the recruiter and your potential future employer
you have made it that much harder for all savvy negotiators at your current company to play their cards close to their chest with this recruiter and your potential future employer
you are assisting in an underwater price-fixing scheme between employers where they will all attempt to pay roughly the same rather than to negotiate with each individual according to value presented
all of the above, even in case your future employer does not hire you
The number of scenarios where this information could be abused is large, one of the more interesting ones is where an employer is actually not looking to hire you but someone else instead and they’re using you to social engineer a picture of the salary scales at your company in order to hire others who may be more aware of their value.
Salary negotiations are an information game and presenting such valuable information for no return at all is a fools strategy.
When asked this question I would suggest you ask the recruiter for his budget in return, or to simply state your salary requirement (rather than your current salary) instead. That way you only volunteer what you could part with without hurting your position too much (and say ‘no thanks’ if that figure is then used to lowball you), or you gain some information yourself which you can then use to make your decision.
But do not state your current salary to someone who is effectively on the other side of the negotiations table, especially not because it isn’t just yourself that you are hurting!