As websites begin to look at virtual goods as a way to offset weakening ad sales, money is flowing into that business. Virtual-goods startup Viximo has raised $5 million, according to Virtual Goods News. Investors include North Bridge Venture Partners and Sigma Partners. A representative did not immediately respond to an e-mail seeking comment. Viximo takes virtual goods — like virtual gifts or avatar costumes — created by outside contributors or its own staff and then distributes them across a network of partners, including makers of Facebook apps and online games. Contributors get a cut of sales.