Since its launch a decade ago, Yahoo Finance has been the Web's favorite free tool for serving the latest stats on stocks. Today the service is getting a Web 2.0 makeover. The new Yahoo Finance is making it easier to build customized charts, embracing videos from Forbes.com and other business news outlets, and letting you add its content to your Web site. By cutting and pasting some code, you can add a Yahoo Finance badge to your blog or other Web site, but it will serve ads alongside your customized stock charts. Yahoo Finance will also serve up threaded message boards designed to make it easier to view a history of postings, which users can rate.