Rarely does a trouncing of analysts’ expectations come as preordained as this. Yahoo’s latest set of quarterly results beat forecasts at both the top and the bottom line. Given Microsoft’s unsolicited bid for the internet portal, it would have been more surprising if Yahoo had merely met expectations.

Unfortunately for Yahoo, beating Wall Street does not mean beating Microsoft. Whenever a company delivers good results in the face of an unsolicited takeover attempt, questions of sustainability come to the fore. Yahoo’s results contained sizeable one-offs. Strip out exceptional items and net income was flat year-on-year. Meanwhile, revenue and profit goals for 2010 remain well ahead of consensus forecasts.