I ran it as a pseudo-workshop: about 2/3's of it was a lecture format, but I also put in time for discussions and brainstorming. People were also encouraged to ask questions or make comments throughout. At first, the group was a bit hesitant about participating - after all, they are used to talks where they come in and listen for 45 minutes, then leave. But, after the first couple of surveys I did (put-up-your-hand-if kind of things), everyone seemed to get more into it.
There were some really good ideas floating around, but we were really strapped for time, so we didn't get to develop them too much. I did mention ahead of time that it will probably go for more than the allotted time; talks usually run for 45 minutes...this one went for an hour and 15 minutes (and only 4 people left before it was done!), and could have kept going.
I definitely need to change and clarify some things before I gave the talk again. I would also run it as a 1.5-2 hour seminar next time, so that we have more time to focus on certain ideas instead of feeling rushed.
I got a lot of compliments about the talk, and a couple graduate students even thanked me for bringing the topic to light (only a handful of people had heard of it before!). I hope that everyone went away with some ideas, or at least an awareness of the Impostor Syndrome and what situations perpetuate it.