Venture Hacks is a site by two entrepreneurs who've been through the mill and want to share the basics they've learned. Their collection of easy-bake startup recipes includes these guidelines for board memberships:
Why are they doing this for free? No doubt to raise their own profiles and expand their personal networks. But one commenter on Valleywag chimed in, "The founders of [immediately successful] companies wouldn't waste time ... founders who have been screwed over have reason to be passionate."