Marissa Mayer's rampant acquisition spree during her first year at Yahoo is all about playing catch-up in the mobile space and investing in R&D, analysts say. But it won't be clear if her strategy is working for a while.
Yahoo has purchased 19 companies since Mayer took over last summer, including its recent $1.1 billion deal to buy Tumblr. And it's likely the company will continue to purchase companies at the same rate next year, said Martin Pyykkonen, an analyst at Wedge Partners.
However, unlike the Tumblr deal, which was primarily a way for the company to buy traffic and target a younger demographic, most of Yahoo's acquisitions so far have been aimed at acquiring talent that can help beef up the company's mobile strength, Pyykkonen said.
(Read more: Tumblr deal gives Yahoo social, mobile boost)
"Most of these fit one description, they are acqui-hires," Pyykkonen said. "A fair chunk of them are mobile, which is where there is the most sense of urgency and rightly so, they need to grow mobile traffic."
In other words, most of these purchases were really a way to snatch up talented engineers in order to weave them into Yahoo's development team to help build new mobile products and improve existing ones so that Yahoo can expand its mobile traffic.
Some of the companies Yahoo has purchased so far include Stamped, the iPhone app that allowed users to save and share recommendations; Ghostbird Software, a maker of iOS photography apps; and its most recent purchase Ztelic, a Beijing-based company that analyzes data on social networks—which it bought just last week.
And it's likely many more acquisitions are to come, analysts say.
"I don't think this is a one-year phenomenon, it does seem like Marissa is more inclined to bring in more external talent and companies than previous management. But I do think the $1 billion acquisitions like Tumblr will be very few and far between," said Mark Mahaney, an analyst at RBC. "I think there may be one large acquisition a year like that."
Pyykkonen also said it's likely Mayer will continue her shopping spree during her second year at Yahoo, but said the company may begin to shift in the type of firms it acquires, focusing more on content companies and investing more in the licensing of content.
But first the company is tackling the challenge of mobile, a space it is very late to enter, Mahaney said.
"The biggest trend is using mobile to access the Internet and there's no doubt that train left the station two or three years ago and has been gaining steam ever since. Yahoo has to catch up to that train," Mahaney said. "There is a gaping hole at Yahoo and she has to fill it."