Interacting with your participants generally increases their learning, holds their attention, helps you make your points, and possibly provides for new information to be shared. Technical presentations hold some different challenges because most of the participants will be writing and taking notes throughout the program. Interactive processes must enhance the learning process and not just provide a break or entertainment.
There are lots of proven techniques, but the introduction seems to work best of all and will, as a general rule, get most if not all of the attendees to participate: Attendees at a technical session generally have a specific need in mind when they sign up for the program. By getting them to open up and share their needs, all the participants stand to benefit from the applications and concerns of someone else. In other words, there is a sharing of goals, concerns, and needs which may become as relevant and valuable to the participants as the materials you present.
Participant introductions serve two useful purposes. First, getting people to say anything at the beginning of a session gets them involved and is a way to establish interest in what you will say afterward. And second, if the participants do not know each other they may find it useful to know who is in the room. On the other hand, introductions can take up a lot of time. People can insert many irrelevant comments and take up valuable time talking about themselves.
If your session is part of a larger program, like a conference, introductions may not fit into the workshop format. The critical consideration in whether to have participants introduce themselves is time. For instance, if there were 15 people in the room for a three-hour session, introductions might be helpful. If there are 60 people in the room for a one-hour program, the time constraint would eliminate the possibility of adequate introductions.