Peter Suber: A field guide to misunderstandings about open access:
The woods are full of misunderstandings about OA. They thrive in almost every habitat, and the population soars whenever a major institution adopts an OA policy. Contact between new developments and new observers who haven't followed the annual migrations always results in a colorful boomlet of young misunderstandings.
Some of these misunderstandings are mistaken for one another, especially in the flurry of activity, because of their similar markings and habitat. Some are mistaken for understanding by novices unfamiliar with the medley of variant plumage, adaptive camouflage, and deceptive vocalizations. This field guide should help you identify 25 of the most common visitors to your neck of the woods.
Leave your binoculars at home. All of these can be seen with the naked eye. With no more than this guide, and some patient observation, every trip to a conference, and even an occasional faculty meeting, can be an enjoyable and educational outing.
Read the whole thing, then save it somewhere handy for situations when someone brings up one of the frequent errors and myths about Open Access publishing.