Online Ads: Goodbye to Real Growth?

Shar VanBoskirk, an analyst for Forrester Research, blames Yahoo!'s problems squarely on the company itself and not on any trouble facing the online advertising industry, which she maintains is still very robust.

"Right now, as an advertiser, it's exhausting to go to Yahoo!" she says, noting that the company is still trying to align all its recent acquisitions so they can function more seamlessly.

VanBoskirk acknowledges a slowdown in certain sectors of online advertising, like display. But she sees plenty more potential in the future. She points out that while many large companies have moved to online advertising, there is still a lot of medium and small businesses not there yet, leaving wide open a huge untapped resource.

Moran also notes that the online advertising industry is constantly looking for more revenue streams in the event that the old ones eventually dry up. Although online search and display ads make up the vast majority of what makes money on the Internet, there has been an effort for companies like Yahoo! and Google to diversify through mobile ads and video. Companies are also trying to realize more efficiencies from their existing technology.

Still, it's hard to say whether all of that will be enough to make up what someday might be lost.

"Video and mobile are extremely small," Moran says. "As an investor, I wouldn't count on that because we don't have concrete evidence that they will be material drivers. There's still some time before that becomes concrete."