All of these 3 presentations are posters. In the meeting, there...

All of these 3 presentations are posters. In the meeting, there are hundreds of them and to get as many presentations as possible there are poster sessions in which the authors will hang their posters on the wall for a certain time. This "one hour" is the time the main author needs to stand by their poster but usually, the poster is hanging there a longer time so that thousands of people can read them.

There are also auditory (oral) presentations, usually lasting perhaps 5 minutes, and 1-minute discussions after the presentation. Sometimes a poster can be a better forum than an oral presentation. The vast majority of the papers in scientific meetings are today posters.