Unofficial Bitcoin Talk Forums API
[C# / .NET] Unofficial Bitcointalk API - Get info from boards, topics and posts
Also since bitcointalk.org is public, you can ready any pages without need to login or authentication. So any simple bot can do the work. Ready the HTML, parse it accordingly so you should be able to read username and other details pretty easily.
Now since you can read every thing you can import it into excel sheet and track you campaign participants from there.
One can do that but only after asking participants to post something on their topic, but isn't asking people to post on topic against forum rules?