For nearly two years, I've been engaged in an activist campaign aimed at improving the performance of Yahoo! ( YHOO). No more. I sold my fund's stake last month. The risk/reward ratio of continuing to hold the stock had become too high.When I started my activism with Yahoo!, I was attracted to the Internet company's strong brand, which continues to drive impressive traffic to its many popular properties. It's still the No. 2 search engine in the world and it's also No. 1 for email. Any new Web company has no hope of emulating those numbers. Microsoft ( MSFT), with its online services division, has been trying to achieve credible numbers in all those areas for the last 12 years -- with little success to show for its efforts. I believed that with better oversight from a new board and management, Yahoo! could finally capitalize on its many strengths. We've had no significant changes at either level. The company is still muddling ahead with just as many priorities, just as many staff and just as many boxes on the organizational chart. I came to the conclusion that this company is doomed to failure with the current board and leadership. Leadership matters. It helps companies to pull away from competitors or to catch up. Unfortunately for shareholders, Yahoo! has lacked a strong CEO for seven years now. Its board has continued to approve excessive pay to executive management and themselves. They will always be remembered for turning down $31 and then $34 a share from Microsoft.