Volunteering as a way of integrating?

Volunteer work is sometimes seen as a good way for foreigners to boost integration in a host country. Is this really the case or does it bring only superficial contact with locals?

Switzerland is a nation of volunteers, with one in four residents doing unpaid work for an organisation. For expats, this kind of activity can be a chance to meet locals and improve language skills. Is voluntary work as a driver of integration? Tell us about your experiences in Switzerland and elsewhere.