These small ribbons attached to your convention badge are a tradition inherited from SciFi conventions. Animé Los Angeles and Offkai Expo are two conventions that are famous for ribbon collecting activities. Making and handing them out could be considered oshikatsu!
See Also
- Ribbons FAQ - an old resource, most of the tips still apply
- Animé Los Angeles Personalized Ribbons - ALA runs their own service for ribbons