According to the 2016 self-reported entry-level hiring report, 66 out of 83 (about 80%) new tenure-track law faculty had a fellowship, and this percentage has risen over time. I think this is primarily because fellowships give you time to write, and it is increasingly difficult to obtain a tenure-track job without a substantial portfolio.
For aspiring faculty in IP and related fields, here are two fellowship opportunities that may be of interest: one at the Yale Information Society Project (where I was a fellow), with applications due January 15 (this Sunday!), and one at the Harvard Project on the Foundations of Private Law, with applications due March 1. Follow the links for more details. And if you know of other current fellowship opportunities that may be of interest to Written Description readers, feel free to add them in the comments.