“Meaningful learning in a community requires both participation and reification to be present and in interplay. Sharing artifacts without engaging in discussions and activities around them impairs the ability to negotiate the meaning of what is being shared. Interacting without producing artifacts makes learning depend on individual interpretation and memory and can limit its depth, extent, and impact. Both participation and reification are necessary. Sometimes one process may dominate the other, or the two processes may not be well integrated. The challenge of this polarity is for communities to successfully cycle between the two.”