The board is responsible for approving all major company actions that aren't delegated to management. In practice, this is mostly: approving option/stock grants for employees, approving financings, hiring and firing senior executives, setting budgets and financial plans, and overseeing the work of management to make sure they're doing what's best for stockholders, and generally talking with management about strategy and plans. They also typically give a lot of help with important hires and making introductions for financings and sometimes business deals. There's no formal vote on other stuff like the product/marketing decisions you asked about, but that would be discussed at board meetings and between them as well, and board members give lots of advice on these topics.

Board members almost always have just one vote each, because its a pain/legal expense to set it up otherwise, and folks hold just one seat each.