Today marked the 20th anniversary of the signing of the Americans with Disabilities Act (ADA), a code of law that has influenced society and tech companies in interesting ways already, and is expanding to influence them even more.

One recent example: feds encouraged schools around the country, notably Princeton and Arizona State University, to drop the idea of requiring students to use e-readers, specifically the Amazon Kindle DX, until the devices were made "accessible." Accessible and acceptable e-readers would need features that work for students who are visually impaired, hearing impaired or have limited manual dexterity.