Finally, networks of practice and formal work groups vary in terms of "expectations about participation". In formal work groups and virtual teams, participation is jointly determined and members are expected to achieve a specific work goal. Participation in communities of practice is jointly determined, such that individuals generally approach specific others for help. In electronic networks of practice, participation is individually determined; knowledge seekers have no control over who responds to their questions or the quality of the responses. In turn, knowledge contributors have no assurances that seekers will understand the answer provided or be willing to reciprocate the favor.