Yahoo!'s (Nasdaq: YHOO) revenue growth story is turning into torture for long-term investors, who've been patiently waiting for the one-day, someday event. And when the company reports its second-quarter earnings later today, it's not likely to present a dramatically different revenue picture in the short or long term, according to most analysts.

As a result, investors are better off keeping a close eye on any comments the company makes on its investments in Asia. Yahoo! holds a sizable 43% stake in Alibaba Group Holdings and a 35% stake in Yahoo! Japan, according to its March quarterly report.

The company valued its Yahoo! Japan stake at $7 billion in March, and its Alibaba stake was worth around $10 billion earlier this year, based on a $23.5 billion valuation t he Chinese Internet holding company assigned to itself as part of an offer to Yahoo! to repurchase some of its shares, according to a Forbes report. The value of the combined investments comes to approximately $17 billion, no small figure considering Yahoo!'s market cap was roughly $18.8 billion at Monday's close.

Asian payoff
Although value investors, who have jumped into the stock lately on the hope that this struggling Internet pioneer will unlock its value with the sale of these Asian investments, are champing at the bit for such a sale, the process may take time. Earlier this year, Yahoo! noted at its analyst day that it may spin off its Yahoo! Japan stake or create a tracking stock. A decision, however, hasn't been made on which path it'll take, noted Ross Sandler, an RBC Capital Markets analyst, in a research note. We may learn more during this evening's conference call.

Likewise, investors should listen for any updates on Alibaba's online auction company and its sale of online payment company Alipay to Alibaba CEO Jack Ma. Yahoo!, along with fellow Alibaba investor Yahoo! Japan, is seeking compensation for the sale of Alipay, which caught both investors by surprise. Yahoo! has been holding onto its Alibaba investment, waiting for the day its would go public. And prior to its sale, Yahoo! had also had similar hopes for Alipay, say analysts.

A payday from Yahoo!'s Asian investments could help investors stomach Yahoo!'s continual decline in a key metric, its quarterly revenues excluding traffic acquisition costs.

Revenue woes
The prognosis for improvement does not look good, given 32% of its 2011 revenues will come from search-related advertising, which has consistently fallen by double digits in the past two quarters. Part of that decline comes from its market share erosion to archrival Google (Nasdaq: GOOG) and partly to its search deal with Microsoft (Nasdaq: MSFT), which has underperformed in delivering the anticipated revenue per search. Although Microsoft is providing a fee to Yahoo! for its underperformance, those fees will no longer be available after March, says Jim Friedland, a Cowen and Co. analyst.

"Yahoo! was already taking a hit but it was getting reimbursed," Friedland said. "But in March, it makes a bad situation worse."

Display advertising revenue, while growing by double digits to 10% in the first quarter, underperformed the Interactive Advertising Bureau's benchmark of 23% growth in the same period. Additionally, Facebook is expected to surpass Yahoo! in display advertising this year and is growing at a faster rate, Friedland said.

Going forward, long-term investors may be better off waiting for Yahoo! to cash in on its Asian investments than count on a dramatic revenue turnaround story.

Fool contributor Dawn Kawamoto does not hold any shares in Yahoo!, but is a frequent user of its email service and loves its corporate purple color. The Motley Fool owns shares of Google, Microsoft, and Yahoo!. Motley Fool newsletter services have recommended buying shares of Google, Yahoo!, and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.