Participants must see that the various front figures at the conference encourage their use of this parallel communication process. If this is not the case then it could easily become perceived as a marginal interest for a minority interest group. Leaders of plenary and group sessions should be spokespeople for the role and value of the messaging system. Take the time to brief them well.
Organizer support is also necessary on the practical side to reduce the time-lag between message formulation on paper and its input into the messaging system for output. Organisers who understand and value the role of the messaging activity will more willingly assist with giving priority time at the photocopier, or remembering the extra two minutes for message collection after each session, or whatever other usually small matters which add up to making the messaging system an integral part of the communication process at the conference.
You may be the organizer or a member of the organising committee, in which case your job will be integration and overview - but it is essential that you have people with specific lines of responsibility for the various tasks (see Roles / P2).
If participant messaging, or one aspect of it, is your sole responsibility, meet as early as possible with others who could be important links with the established programme (eg. working group facilitators); also those involved with the organisational aspects (rapporteurs, sound recordists, etc.). You are likely to find many areas of cooperation.