) --Merger activity amongst technology companies is nothing new. Start-ups are often venture-backed, and very few of them become large enough or profitable enough to pull off an IPO and need to raise enough money to repay their investors.

Luckily, for tech entrepreneurs, there are a handful of large acquisitive companies out there.


(CSCO) - Get Report

has acquired over 100 companies, and


(GOOG) - Get Report

has done its fair share of acquisitions as well. Sometimes it's cheaper to purchase a successful business than recreating it oneself.

Although they often compete for the same companies, the acquisition strategies of the Internet giants vary. Some companies like to do a lot of acqui-hires (buying companies with the intention of shutting them down, just to get the talent). Others, focus on larger scale billion dollar deals. Sometimes the companies are integrated. Sometimes they remain as standalone companies. Some acquisitions ultimately fail.

Companies like Google, Yahoo!, and others all approach deal-making in different ways.

Google is one of the most acquisitive tech companies. Google has made over a dozen acquisitions in the past year and over 100 in the past five years. Some of them have been huge deals, too. Google acquired

Motorola Mobility

last year for $12.5 billion. Android and


were also brought in through acquisitions.

Although Google shells out the big bucks for some companies, many of Google's acquisitions are small enough that they wouldn't trigger anti-trust review. (The threat of anti-trust scrutiny looms over Google, which is said to have been one of the reasons they couldn't reach a deal with Groupon). Even if acquisitions are ultimately cleared, the process can drag out for a year, halting progress for technology companies.

Sameet Sinha, analyst at

B. Riley & Co.,

predicts that many of Google's future acquisitions will be smaller tuck-ins. Sinha expects that Google will continue to buy companies that will advance its mobile strategy. As for the often-cited


acquisition, Sinha says it's still possible. It would ultimately come down to Twitter's price.

Although Google's acquisition of YouTube was successful and Android "turned out to be a home run," it's worth noting that not all Google acquisitions work out.

Foursquare founder

Dennis Crowley's location service, Dodgeball, got shut down.


Travel Guides were recently bought back by the name-bearing author, only months after Google acquired the brand. Given the number of deals Google makes, it's inevitable that not all of them will pan out.

Given Marissa Mayer's Google background, it should come as no surprise that



is doing a lot of deals. CEO Mayer is on a bit of a shopping spree, purchasing a dozen companies since last fall. Although most of these have been acqui-hires, Yahoo! just doled out $1.1 billion for popular blogging service,


. Yahoo! is also reportedly making a bid for online video provider,


. These deals are expensive, but Yahoo! has the cash, with more than $2 billion left on its balance sheet.

Although Yahoo! has encountered past difficulties with acquisitions like Geocities, it remains to be seen how other brands will perform under a Mayer-led regime. Although Tumblr was expensive, it has the younger demographic that Yahoo! is vying for. While many tech companies try to appeal to a younger demographic, it's worth noting that teens also happen to be too young to remember Yahoo!'s fall.

Many people have questioned the high price paid for low-revenue Tumblr, but Sinha says Marissa Mayer takes a long-range view. She's thinking, "what's going to be huge five years down the line?"

Don't expect Yahoo! to try to become the next Facebook. "Yahoo! wants to be the Switzerland" of tech companies, Sinha noted. "They want to be neutral so that they can partner with these online giants." Sinha predicts Yahoo! will mostly make "small acquisitions to increase their value as partners to Google or Apple or Facebook." But whatever the strategy, "she needs to make some drastic moves and she knows that." Look for big deals and other big changes at Yahoo.


(FB) - Get Report

business model has gone under a lot more scrutiny this past year, now that it's a public company. One major shift in strategy, is it's attitude towards acquisitions. Although it still makes its fair share of acqui-hires, Facebook has now made bigger, grown-up purchases as well.

Facebook spokeswoman Ashley Zandy says that in addition to "great people," they are now looking to purchase technologies and products as well. Facebook's recent purchase of cloud app builder


was "a great step forward for the platform." This year's Atlas Advertiser Suite deal "fits well with the monetization strategy."

Its biggest acquisition to date, was


last year, purchased for $736.5 million in cash and stock, down from an initial offer of $1 billion dollars, caused by the decline in Facebook's stock.

The popular photo-sharing app has grown to 100 million monthly active users, up from 22 million last year. Telsey Group's Forte said Instagram was a "defensive acquisition," and that Facebook needed a "fast growing social networking site that was attracting a lot of young users." However, it's still unclear how Facebook intends to monetize it.

Facebook was reportedly in talks with


, the Israeli-mapping based app, but talks fell through. However, Sinha expects Facebook to stay acquisitive in the future.



is less acquisitive than some of the other public Internet companies, having made only one significant acquisition this past year. In April, LinkedIn acquired news reading app, Pulse for $90 million. This purchase is consistent with LinkedIn's efforts to become a forum for news and other business content. As LinkedIn's Krista Canfield puts it, LinkedIn envisions itself transforming into the "definitive professional publishing platform."

LinkedIn also purchased presentation-sharing community, SlideShare, for $119 million in a cash and stock deal last year.

Telsey Group

analyst Tom Forte says that acquisitions like Pulse and SlideShare "fit with their product. LinkedIn looks for "companies that improve their ability to build the leading professional social network." Forte predicts LinkedIn will continue to look for companies that will "advance their content-related efforts" and also help them "move forward with mobile." Says Forte, content has "proven to be very effective at generating revenue" for LinkedIn.


CEO Sam Hamadeh finds it curious that LinkedIn hasn't been doing more deals. LinkedIn has the access to capital, but hasn't been deploying it. Observes Hamadeh, "when larger companies are shopped for sale, LinkedIn has a look but almost always passes. LinkedIn window-shops, but rarely buys." However, Hamadeh says the minimal deal activity isn't necessarily a bad thing. " With a business model already quite set at this point, and so many tech acquisitions that go bad, Linkedin's strategy may be more cunning than it appears." Whether they are missing out on opportunities or showing necessary prudence, LinkedIn is less acquisitive than many of its peers.

E-commerce giant


(AMZN) - Get Report

has made dozens of acquisitions over the years. Although many of these were commerce-related, Amazon recently bought book recommendation site


for $150 million. Goodreads complements Amazon's substantial book-selling business. Another large acquisition, audio content provider, was purchased several years ago for $300 million.

Still, Amazon's largest deals were already in the e-commerce space.


, known for its shoes and other apparel, was purchased by the e-commerce giant in 2009 for $1.2 billion.

Kiva Systems

, which uses robots to automate order fulfillment, was purchased last year for $775 million.


, the parent of, was acquired in 2010 for $545 million.

Jeffery Bistrong, managing director at investment bank

Harris Williams

, says he is "very impressed with Amazon. They have moved into segments that their competitors haven't. Going forward, expect Amazon to acquire "niche leaders with unique customer experiences where they can drive significant revenue synergies." Perhaps they could buy a popular commerce site, like

Warby Parker


Gilt Groupe

. As Hamadeh puts it, "Amazon acts opportunistically to move into a new market where it isn't yet the market leader."

--Written by Katie Roof in New York--