This is very cool! Thanks for sharing Pmocz!

One thing you might consider adding into this data set is that some states in the USA publish state university employee salaries. For example, both Wisconsin and Minnesota share the salaries for lecturers, faculty members, etc. which would substantially grow your salary count without waiting for individuals to find your site and upload their own data. What may be challenging, is connecting the additional details like date of PHD and department. And of course, this method would skew your data set towards public institutions substantially.

Best of luck with this project!