If you are presenting a workshop/class in which you expect the participants to interact with you and each other, at the first meeting you may want (or need, depending on the material to be covered) everyone to go around the room to introduce themselves and say why they are there.
Unless you are specific in limiting them to only saying their name, be aware that this exercise will most likely take MUCH longer that you think. You may feel that it’s unwelcoming to set a time (ideally with a device that audibly indicates time has expired to everyone), but in my experience people so seldom get to talk with others who listen they do not know how much time they are taking.
My worst experience of this was at the beginning of a weekend retreat with a spiritual leader who arrived at the venue jet-lagged and sick, with a co-leader also not in great shape. We started going around the room of about 25 women at 7:30pm. By the time it was 12:30am we were still 5 people from the end, and had dealt with several people who claimed to be in need of exorcism, and others who would not take a hint to wrap up – the leaders just did not have the energy to stop the flood of TMI!