The company saw its market share in search hit 13.4% in May, a decline from 13.5% in April and 15.9% a year earlier. That's an all-time low. Rivals Google (GOOG) and Microsoft (MSFT) both reported gains. (Microsoft owns and publishes Top Stocks, an MSN Money site.)

Meanwhile, Yahoo's new board of directors is struggling to right the Internet media company's tottering ship. "In almost completely upending its director roster over the last several months, Yahoo has given itself a new lease on life, but has also created a significant challenge in forming a cohesive governing structure that can work together in fixing a cohesive governing structure that can work together in fixing all that ails Yahoo," according to Kara Swisher at All Things D.

Swisher reports that the 11 board members, including activist investor Daniel Loeb, have just as many ideas of what is best for Yahoo. Whether this many cooks will spoil the broth remains to be seen. The board's moves so far -- such as choosing Ross Levinsohn as the interim CEO -- don't inspire confidence. Levinsohn's claim to fame was being part of the News Corp. (NWSA) team that acquired MySpace, one of the biggest acquisition disasters in history.

Yahoo is a vestige of an earlier Internet era when websites tried to be all things to all people. No site launched today would attempt such a wide variety of offerings as fantasy football, email and celebrity news, because there is nothing that ties them all together.   Niche sites that are more targeted pose a serious challenge to the company. Publishers are also leery of the company's increasing interest in producing original content.

Add to this scenario a weakening macro environment. The latest IAB Internet Advertising Report estimates that Web advertising spending rose 15% to $8.4 billion in the first quarter. That represents a slowdown from the 24% gain seen in 2011. Some of the decline may be attributable to the law of large numbers, because there are only so many times anything can post huge gains.

But advertisers are clearly getting skittish because of the faltering economic recovery.
They are getting pickier about where they spend their money and will no doubt ask for and receive steep discounts on advertising rates. Yahoo also will need to convince marketers that its platform remains relevant in the age of Facebook (FB) and Twitter, which won't be easy.

Of course, Yahoo isn't standing idly by and watching its business deteriorate. The website  announced Wednesday a content-sharing agreement with Comcast's (CMCSA) CNBC cable network. While the partnership -- and a similar one with Walt Disney's (DIS) ABC -- is positive, it won't add much to Yahoo's bottom line, as the companies will split any advertising revenue that the deal generates.

Every move Yahoo makes raises as many questions as it answers. Investors should avoid the stock for the foreseeable future.