| My advice would be to send handwritten notes and also address each note to a particular person or group by name. Something short and to the point would be best. Maybe something like "Dear (Name), Thank you for stopping by our booth and giving us the opportunity to discuss with you what our organization is about and how we might be of service to you. We (I) look forward to further dialogue with you concerning how we might be of service to you in the future. Please let (us, me) know if there's any further information that you might need about our organization. Sincerely, (Your name or name of your organization.)
Something along those lines... | 
Linear Mode
