Starting in June, a series of stories started documenting a global intelligence operation last seen on Showtime's 'Homeland.' Those PowerPoint slides, provided by National Security Agency whistleblower Edward Snowden, taught businesses that the convenience of the cloud cuts both ways. By tapping into the pipes exiting data centers belonging to Google Inc., Microsoft Corp. and other tech vendors, the NSA found a 'convenient' way to vacuum vast amounts of data. The NSA's reach was also revealed to extend to cellphone data

In the wake of the revelations-henceforth called the 'Snowden Effect'- tech vendors have worked to identify and apply security fixes, while assuring clients that their data remains safe. Abroad, businesses and politicians have touted local solutions. But this is just the beginning. Mr. Snowden is said to retain many more documents and it is quite likely that the Snowden Effect will remain the top tech industry story of 2014.

Meanwhile tech vendors in 2013 had their hands full operating multi-billion-dollar businesses. While many of the younger companies have achieved success, traditional and legacy vendors have struggled. CIO Journal looks back at the most significant news generated by some of the world's leading tech giants in 2013.

Microsoft: Microsoft announced in August that CEO Steve Ballmer would retire in 12 months. Mr. Ballmer, who took the CEO reins from founder Bill Gates in 2000, is in the midst of transforming Microsoft from a PC-based software maker to a device and services company, with an emphasis on mobile and cloud computing. Mr. Ballmer admitted that evolution was taken too long, setting the stage for his departure. On Dec. 17, John Thompson, Microsoft's board director, said Microsoft would name Mr. Ballmer's replacement - from a pool of 20 people - in 2014.

Google: The company's biggest reveal this year was its strategy to place 'moonshot' bets on game-changing technology efforts, such as driverless cars. The company this year released to limited availability its Google Glass wearable computer. Google also unveiled Project Loon, an audacious effort to build a global network of high-altitude balloons that bring Internet access to people in remote areas. The company is also mounting a significant foray into robotics. Google is also targeting enterprise customers with cloud infrastructure software, which it released to general availability in December.

Apple Inc.: For Apple, it was another year, another refresh of its iPhone and iPad. In September, Apple's iPhone 5S received plaudits for its fingerprint scanning technology, which promises to make it easier and more secure for users to log in to their device. Announced in October, the iPad Air is a thinner, lighter but souped-up version of its market-leading tablet computer. The company also lured Burberry CEO Angela Ahrendts to run its retail and online store businesses. But CEO Tim Cook, along with the company's stock price, took some hits for failing to bring the long-rumored Apple TV product to market. However, he hinted that a wearable computer of some sort could be on the horizon. Anyone up for an iWatch?

Hewlett-Packard Co.: Hewlett-Packard Co. faced significant challenges in 2013, the second full year in CEO Meg Whitman's multi-year turnaround plan. The company said it would focus on making more competitive servers, storage and networking gear, as well as analytics software. Although H-P is accelerating research and development to boost sales, smaller commodity hardware and cloud software rivals are pressuring the company. Disappointing sales in H-P's enterprise group prompted Ms. Whitman in August to replace division head David Donatelli. In November, H-P posted weaker fourth-quarter sales, the ninth consecutive top-line decline. Ms. Whitman said 2014 would be a 'pivotal year' for H-P.

IBM Corp.: Like H-P, IBM Corp. is shaking up leadership as it struggles in some of its core businesses. Following disappointing third-quarter results in October, CEO Virginia Rometty reassigned James Bramante, the IBM senior vice president who ran growth markets. IBM has missed Wall Street's revenue targets in six of the last seven quarters. IBM also disappointed some customers, some in grand fashion. In August, the premier of the state of Queensland in Australia, Campbell Newman, said he had banned IBM from entering into new contracts with the state until it improved its governance and contracting practices. The company has also been at loggerheads with state officials in Pennsylvania, Indiana and Texas over technology implementations.

Dell Inc.: Following a contentious buyout battle with Carl Icahn and other investors, Dell Inc. went private in November to work on its strategic reinvention as a cloud software and services company. The company is helping customers pick and integrate public cloud software from vendors such as Microsoft and Google. To cultivate innovation, the company is investing $300 million over the next several years in startups. Dell said it hopes this effort will generate capital gains for the company, while providing a window into emerging technologies in cloud, security, storage, mobility and analytics.

Oracle Corp.: Oracle CEO Larry Ellison infamously skipped his final keynote at the business software maker's customer conference in September to watch his yacht take the America's Cup. The move overshadowed major announcements the company made at Oracle OpenWorld, including a deal to run Oracle software on Microsoft's Windows Azure cloud service. In an acknowledgment that more software is moving to the cloud, Oracle in June partnered with rival Salesforce.com Inc. to integrate business applications in the cloud. Oracle in December acquired Responsys Inc., a maker of cloud marketing software, for $1.5 billion.

SAP AG: On the whole, it was a relatively quiet year for SAP, the enterprise software maker that is the frequent target of Mr. Ellison's ire. The company made available its HANA in-memory database to run predictive analytics against data housed in SAP's business software. The company also rolled out a cloud version of HANA for businesses. Also significant: SAP said Jim Hagemann Snabe, co-CEO with Bill McDermott, will swap his current role for a position on SAP's supervisory board in May 2014. But SAP also closed out 2013 with some bad news. Avon Products Inc. said it is cancelling a $125 million SAP software system after sales workers in Canada left because it proved too onerous to their routines.

Salesforce.com Inc.: Cloud software maker Salesforce.com spent the last seven years buying companies in marketing engagement, social media, and human resources. In June, it paid $2.5 billion for ExactTarget, its biggest acquisition to date. In November, the company revealed how those purchases fit into its Salesforce1 strategy. Its mission is enabling sales workers to collaborate with coworkers to sell products and services, at any time, from any device, through Salesforce.com's cloud platform. In addition to the Oracle deal, Salesforce.com also partnered with H-P to run software on the systems provider's infrastructure.

BlackBerry Ltd.: Perhaps no company has endured a more difficult time in 2013 than BlackBerry Ltd., whose business has stumbled as the iPhone and Android phones have soared. After failing to sell many phones based on its revamped BlackBerry 10 operating system, the company in November abandoned a $4.7 billion plan to go private, choosing to continue as a public company with new leadership. BlackBerry replaced CEO Thorsten Heins, who failed to right the ship after he was promoted from within to turn the company around almost two years ago, with former Sybase Inc. CEO John Chen. On Dec. 20, BlackBerry reported a $4.4 billion third-quarter loss quarter, after which Mr. Chen said 2014 would be an 'investment' year for the company.