Competition in the technology sector is heating up as the biggest and most successful companies are expanding and stepping on each other's toes.

Early on Tuesday, Microsoft launched Office 365, seen as a direct response to the cloud-based Google Apps.  Office 365 features web browser versions of Microsoft Office and real-time team collaboration, which is similar to what Google Apps offers.

Then again, it was Google who first challenged Microsoft for the highly-lucrative multi-billion dollar enterprise software market with the introduction of Google Apps a few years ago.

On this same day, Google introduced to the public the Google +, a social networking service.  It's got photos and groups, much like Facebook.

The key difference is that Google + is inherently organized into separate groups, so it's social networking for specific interests with specific people rather than for everything with everyone .  It also prominently features video chat.   

Google hopes these differences will enable it to carve out a space in the social networking market.

Tech companies are increasingly straying from their original core business because of their insatiable desire to grow.  Indeed, the biggest tech companies don't seem happy to simply protect their dominance in their respective niche markets and become low-growth cash cows.

Another reason is that many of them are sitting on billions of dollars in cash; instead of returning that money to investors, they're plowing it into new projects.

Sometimes, the expansions are strategic because of potential synergies.  For example, the data collected from Google+ could help Google Search come up with more targeted advertising. 

Lastly, tech companies are obsessed with avoiding obscelence.  For example, Yahoo! missed the search engine bandwagon and it will probably never be the dominant force it once was.  Google is now trying to not miss the social networking bandwagon and defend its title as the 'King of the Internet' from Facebook.