Today, many companies basically ban GPL-licensed or otherwise copyleft software projects, perhaps apart from a handpicked list of exceptions, because they don't want to deal with the hassle. MIT, fine, GPL, no. And that's pretty sad. Because it means that if write a new project you need to choose between "people will use it but it won't be copyleft" and "copyleft but a sizeable part of the community won't touch it with a 10ft pole".