[mattlutze]

Unless many, many of the members of your professional network are quite homogenous to your skill set, location and market sector, and unless a large number of those actually give you accurate information, you really can't rely on them to find out what a typical salary is.

And the value of a position at two companies depends more on internal factors than on a job title. Senior Developer at X simply won't be worth the same as Senior Developer at Q.

If you know internal numbers, you can maneuver the upper-hand as an employee. But the best you're generally going to do is a ballpark, and have to leave it up to the company to determine how much they want you vs. the other candidates they have.