It may have been a very tough year for IT business and startups worldwide. Be it Automobile Industry, Aviation or Heavy Metal Industries, all markets felt the heat of recession but regardless IT fared better than most.

In spite of worst economic meltdowns in history, acquisitions among big vendors continued to reshape the market, operating-system wars extended to mobile battlefields, microblogging became a powerful source of real-time information, and the take-up of small, Net-connected devices was stronger than ever.

We are tried to re-compile the list of some major takeovers which are substantial enough to change the future of computing. We are talking about some multibillion dollar mergers and acquisitions, where the Big gets even Bigger.

Oracle eclipses the SUN @ $7.4 Billion

This Merger can be coined as “father of all the Tech Mergers” announced last year. If the announced the deal went through, Oracle,  the industry’s largest database software vendor would get an entry into the server and storage markets worldwide.

The acquisition, still pending, was announced in April, and may even be blocked because European regulators are contending that combining Oracle’s technology with Sun’s open source MySQL database would violate competition laws. Lets see if this deal goes through.

Xerox snaps up ACS in $6.4 billion

Another major takeover, Xerox pays about $6.4 billion in cash and stock for Affiliated Computer Services (ACS), a large IT and outsourcing firm. With this merger Xerox hopes it will give it a bigger foothold in the business services space. While the deal will surely boost Xerox, investors wondered whether it overpriced the deal.

Calling the ACS deal “a game-changer” for Xerox, Burns, CEO of the company, said it would help Xerox “expand our business and benefit from stronger revenue and earnings growth.” The deal will triple the service component of Xerox’s revenue to roughly $10 billion annually from $3.5 billion, according to the company.

Dell – Perot Catch-Up Deal worth $ 3.9 Billion

Buying Perot was a part of Dell’s plan to expand its footprint in the IT services market, which was  a necessity in a time when hardware sales were falling. Dell offered a staggering $3.9 billion for Perot Systems, a 68% premium over Perot’s actual stock value. Dell’s purchase can also be seen as a response to rival HP’s $13.9 billion acquisition the previous year of EDS — another services company founded by Perot.

Cisco-Tandberg worth  $3.4 billion

Cisco, already a major player in collaboration products with WebEx and TelePresence, signed an agreement in October to purchase videoconferencing vendor Tandberg, which makes both video devices and network infrastructure products. The acquisition, if completed, could have both a direct and indirect impact on Cisco’s bottom line, because expanded use of videoconferencing may increase network traffic, letting Cisco sell more switches and routers.

HP Acquires 3Com For $2.7 Billion

HP launched a straightforward assault on Cisco in their own Game of Networks. HP’s increasing influence in data center networking and convergence markets will have a big boost with its purchase of 3Com, a maker of switches, routers and security products. HP says the acquisition will further its data center strategy “built on the convergence of servers, storage, networking, management, facilities and services.” The acquisition of 3Com also help to expand HP’s Ethernet switching offerings, add routing solutions and significantly strengthen the company’s position in China thanks to 3Com’s strong presence in China. The transaction is expected to close in the first half of 2010.

But is a wave of mergers necessarily a good thing?

Not always. And particularly not right now when it comes to web and social media startups, many of which are still more focused on innovation and building up audiences than on making profits. Rushing them into deals to fulfill long-delayed plans for an exit strategy could derail the evolution of a strong business plan.

From an investment standpoint, founders and venture capitalists have good reasons to cash out now. Market caps of public tech giants are rising — the Nasdaq gained 15 percent last quarter alone – and so are their cash stockpiles: Microsoft is sitting on $49 billion in cash; Google, $24 billion. The IPO market is coming back to life, but not enough to meet the pent-up demand. And high-profile deals like the ones we’ve seen recently have a way of spurring on other acquisitions.

The risk is that, just as the quality of IPOs tends to deteriorate the longer a market boom lasts, a wave of M&A deals will bring on marriages that make less and less sense.