When a town hall meeting ends, the work isn't done. A successful town hall can reach more than just the 20 or 200 people who showed up to the live event.
1) Publicize the results
Use the notes, photos and/or video that you took during the event to write a story about it. The focus should be on the everyday people who stood up and talked. Include their photos and quotes.
Write it like a newspaper story and post it on your website. Send it to the local media as a press release. And finally, share it by e-mail to the list of people who showed up.
2) Thank the participants
Send an e-mail to the sign-in list and thank everyone who showed up. If they left a phone number instead of an e-mail, take the time to call them up and thank them personally. It's worth the time.
3) Keep working on the issue
It's doubtful that a single meeting fixed whatever problem you were focusing on. Keep in touch with a core group of citizens and stakeholders to continue focusing on this issue and getting things done.
Use the local media and your e-mail list of participants to keep people (a) updated about what's happening and (b) informed about what they can do to help.