Still "Building the Structure of the New Society...."
...the common treasuries they held were a locus of available capital outside the purview of early state capitalism. Mutual hospitality among members allowed for labor mobility that thwarted the monopolistic hiring practices of early state capitalists. And the use of common oaths directed loyalties toward an object other than the state and its established church.And according to E.P. Thompson, there were some interesting synergies between the friendly societies, the early trade unions (themselves with roots in fraternal lodges), and the cooperative and labor-note movements; laborers on strike were able at least partially to replace their lost wages by engaging in artisan production and exchanging their wares through cooperative exchange systems.
Black Guile's post includes this brilliant passage:
Early, radical mutual aid societies (which were, after all, Proudhon's inspiration) provide a good example of how to build effective counter-state institutions. They also provide yet another warning to my anarcho-capitalist friends that firms under an anarchist future will probably not look like currently-existing firms. Since the state beat down, and then smothered, mutual aid socieities, while it has fostered the hierarchical corporation, which one are we likely to have more of in the absence of the state? (Emphasis mine)
Black Guile also links to some good material at Takver's Radical Tradition site, the best online collection of historical material on mutuals and friendly societies that I know of.