Facebook just keeps on sliding. The stock fell again Tuesday, dropping under $30 per share and closing at an all-time low, $28.84, a 24 percent drop from its initial public offering price of $38 on May 18.

There’s no doubt that Facebook’s debut has been disappointing for investors who had gone into the IPO with high hopes about its possible performance. Nearly everything about the offering has failed to meet expectations. From the beginning, Facebook was plagued by opening glitches on the Nasdaq, which were followed quickly by reports that the debut’s underwriters may have given more information to select investors

Stumbling out of the gate doesn’t necessarily spell disaster for a company. Analysts have compared Facebook’s public debut to that of another tech titan, Amazon.com, which quickly fell below its opening price of $18 after its 1997 debut.

“Like Facebook, Amazon was ‘optimally priced’ ” for its market debut, noted Bill Gurley of Benchmark Capital. “The stock broke issue and stayed below until July 6. No one remembers.”

Still, questions remain about Facebook’s viability that have little to do with its stock price. Technology analyst Rob Enderle said it’s difficult to draw a direct parallel between Amazon and Facebook, because the social network doesn’t offer clear goods or services. Amazon succeeded by solidifying a strong retail presence and then using its strengths to spread into other businesses.

“Amazon had a retail core that allowed them to convert into a viable business,” he said. “You have to understand what you do for a living, set a solid foundation and then build into adjacent areas.”

To succeed, Facebook will have to move beyond the problems of its debut and show it can move its product forward — something not all analysts are convinced the company can do.

The main problem with Facebook’s business model, analysts say, is that the company hasn’t shown it can sustain major advertising revenue off of its social data: General Motors announced that it was going to stop advertising on Facebook just days before the IPO.

Facebook has also failed to generate the same kind of revenue through mobile devices as it has on traditional computers, a growing problem as the site’s audience shifts to smartphones. The company is trying to address this with a combination of acquisitions, such as its $1 billion purchase of Instagram in April, and attempts to innovate on mobile ad formats. There have also been reports that the company may be trying to fix its mobile problem by working on its own smartphone.

Enderle said that Facebook should be wary of doing anything too far out of their core business before figuring out its revenue problems. He said that the company is in danger of losing focus after producing one good product.

“Facebook needs to shore up their foundation,” Enderle said . The company’s finances stream, he said, is not secure. “They haven’t locked up revenue,” Enderle said. “Until they do, wandering off is probably a mistake.”

(Donald Graham, chairman and chief executive of The Washington Post Co., is a member of Facebook’s board of directors.)