(Updated Sunday 1.36PM)
If your coauthors aren’t already on the site, you have only 1 or 2 options. The option they want you to use is to provide them (the sites) with your coauthor’s email address so they can Spam them (cough, invite them) to join up. This I refuse to do. ResearchGate now finally lets you add an author who is not a RG user, but Academia.edu seemingly still refuses (Sunday update: You can add a phantom coauthor in Academia by adding a name but with a fake email address). But this process creates a new problem. You’re creating a new phantom user in their database. This adds to the problem of keeping track of actual researchers across multiple platforms, something that projects like Orcid are trying to prevent.
This problem is even worse when it’s the first or last* authors who aren’t on the platform. I worry that it’s giving the false impression that I’m unfairly taking credit for someone else’s paper when I’m actually the nth author. Once again at least RG lets you put one of these phantom authors as first author but Academia won’t. My crappy solution for now is to put a ranty disclaimer at the top of the Abstract field complaining about the problem and that there are several other authors who need to be acknowledged. This is far from ideal but it’s the best I can do for now.
Yes I know their business model is to suck in more users but can’t they do that in a less sucky way?