The world's biggest social networking site Facebook, which launched Facebook for Business earlier this week, and the youngest social networking phenomenon Google+ (or Google Plus) are heading towards a bloody face-off that will leave only one clear winner.

Google+, launched June 28, was off to a flying start and its growth has been meteoric. Within the first three weeks, the site boasted 20 million users and within a short span of time, it has become the 42nd most-visited social networking site and the 638th most-visited site overall in the U.S, according to Web analytic firm Experian Hitwise.

However, there were speedbumps on the way - Google's decision to purge individuals who used false names and businesses from Google+ was met with heavy flak and it opened a floodgate of complaints - while some individuals said they used their real name and had their account deleted anyway, others said they should be able to use a pseudonym to protect their privacy. Businesses also complained that Google ignored the needs of the corporate.

Moreover, Google+'s limited access (Google+ is in beta phase and users are allowed to use it on invite-only basis) has disappointed many users. After checking it out and setting up a basic profile, Google+ users are exiting the site and seldom returning because a critical mass of their friends aren't on it yet.

Not surprisingly, Hitwise said that after visits to Google+ had soared 283 percent for the week ending July 16 compared to the week before and 821 percent for the week ending July 9 compared to the week before that, for the week ended July 23, Google+ received only 1.79 million visits (down three percent compared to the previous week) and the average time spent on the site was also down 10 percent, compared to previous week, to five minutes and 15 seconds.

Hitwise hasn't explained the reasons for the traffic drop and Google+ has suggested that one shouldn't take the data too seriously as it excludes "critical" aspects such as Google+ visits through mobile apps or APIs, which means that users accessing Google+ using the Google+ app on their iPhone or Android smartphones aren't being counted. Google has a point here because the Google+ iPhone app, which was launched last week, has risen quickly to the top of the App Store rankings (and beating Facebook iPhone app in the process) and there's a good chance that mobile users could have made up for the losses that Hitwise is reporting. Also, the Hitwise figures are just for the U.S. and do not include countries like India, where Google+ has seen an uptick.

Meanwhile, Facebook didn't hesitate to take advantage of Google+'s troubles. The site quietly and quickly launched Facebook for Business that walks the businesses through Facebook's "powerful marketing tools" and teaches them how to create a Facebook Page, build relationships with members of the Facebook community, and use Facebook Ads and Sponsored Stories.

"Facebook allows small businesses to create rich social experiences, build lasting relationships and amplify the most powerful type of marketing -- word of mouth," a Facebook spokesperson wrote in an email to Reuters. "We created Facebook.com/business to make it even easier for people to reach these objectives and grow."

"Business owners can learn best practices for creating a Page and engaging customers in a two-way conversation to answer questions, get valuable feedback, and to reach their friends," a Facebook spokesperson wrote. "Businesses can learn how to find new customers before they search for them using Facebook's targeted Ads, and bring customers from the Web into their stores. And we want to inspire small businesses by seeing how other businesses have found success on Facebook by sharing their stories."

Earlier, Facebook also had teamed up with Skype to offer the multi-user video conferencing feature, a week after Google presented Google+ Hangouts, that allows up to 10 users to see each other simultaneously on video and talk.

Facebook's latest move wasn't surprising because it perceives Google+ as a threat. Why else would Facebook go on an overdrive to delete Google+ ads on its site or try to keep Facebook users from exporting Facebook contacts into Google+?

Though Google+ is a fledgling site compared to Facebook, which boasts of 750 million users, it's not surprising why Facebook may consider Google+ to be its greatest threat.

According to Search Engine Land's founder Sullivan, Google is "the only company well positioned to launch a Facebook alternative."

"People like alternatives. Twitter doesn't offer a full-fledged alternative to the Facebook experience. Google does," he says.

Charlene Li, founder of the Altimeter Group, agrees. She sees a clear potential for success in Google+. "It's got the whole package to take on Facebook," she says.

According to technology analyst Rob Anderle, "Google+ has aspects of Twitter, Facebook and LinkedIn in it, and folks are a bit overwhelmed with all of the different social networking services."

"Folks have also crammed these other services with tons of 'friends' they don't really know, and the sheer volume of activity has weakened the quality of the experience," Enderle told ABC News in an email.

And, that's true because compared to other social networking sites, Google+ seems to offer the best user-friendly experience and one doesn't need to be high on the learning curve to get going.

Moreover, Google+ offers a one-stop-shop social networking experience for people who want to link to friends and family, but don't like using multiple sites. Currently, Facebook is the to-go site for family and friends, LinkedIn is for professionals and Twitter is for micro-blogging. The experience could turn out to be quite overwhelming, and Google+ could be the perfect solution for it offers various ways to connect to your friends, family, co-workers and more - through video and texting, among other things - while at the same time boasting of privacy and content-sharing features that are easier to use than Facebook's.

Other aspects of Google+ that makes it a threat to Facebook are:

Privacy Controls: Privacy issues have haunted Facebook and Twitter for long. Anything posted on them is displayed for the world at large to see and horror stories of content not meant to be seen by family, friends or co-workers are not new. However, both Facebook and Twitter have done little to address the issue and have adopted a cavalier attitude towards the problem.

On the other hand, Google has specifically attempted to address the problem by introducing Google+ Circles that allows users to separate their contacts in customized groups. Unlike in Facebook where everybody is a friend including your boss or your boss' cat, Circles users can group their contacts under specific names such as Family, Friends, Acquaintances, Co-workers, in fact, anything at all.

Circles, in fact, could be Google+'s biggest strength as neither Facebook nor Twitter allows you to group your contacts and both force users to share anything and everything they post with all their friends, with few options to control who sees what. Google+ allows users to share information with only those contacts or group of contacts they want to share with.

Integration: A major strength of Google+ and its advantage over Facebook is integration. Almost all the existing Google online services and products, from Search and Documents to Email (Gmail) and Video, will be built into Google+ social networking features. It will allow the user to monitor all Google+ events, such that the user never misses out on anything, anywhere, anytime.

Search: Google's most powerful weapon is its unrivaled search engine. If Google integrates its own Google+ live feed Sparks with the Search service, it could make a huge dent in Facebook's popularity, because although Facebook has had a huge headstart as a social networking site, it has made little or no penetration into the search engine market.

Data Liberation Tool: Facebook users have often complained how difficult it is to delete your profile or export your data elsewhere if you want to leave the site for good.

Google+ has circumvented this problem by introducing "data liberation" tool in Google+ which allows you to pack up and take your data away from Google+ should you decide to leave the service.

Hangouts: Perhaps the greatest strength of Google+, the multiuser video conferencing feature allows up to 10 users to see and talk to one another at the same time. The one with the loudest voice takes the center position. In reponse, Facebook integrated Skype video conferencin into its chat function. But Hangouts has already sparked users' imaginations about its potential business uses, with many seeing it as the future of webinars.

However, Facebook isn't one to give up without a fight. Since it became public in 2006, Facebook has come a long way, killing Friendster and MySpace in the process, and it is unlikely that it will let the challenger Google+ poach its users easily.

Facebook may not have Google's search engine or Google's powerful ecosystem of products and services, but it has found a good partner in Zynga, whose social games keep Facebook users engaged on the site for hours and make them keep coming back for more.

The site has also done a good job in keeping a lot of its user-generated content off-limits to the Google search engine.

And though Facebook for Business is not new because already Facebook is being used by corporate marketers to reach out to the site's 750 million users, it is going to be a wake-up call for Google+ and the site has many things to address.

For instance, users have grumbled that the search function is absent in Google+ even as developers expressed disappointment that Google, otherwise a developer-friendly company, hasn't yet made it possible for them to create third-party Google+ tools and applications.

In conclusion, Google+ has the trappings of a Facebook killer but it needs to be attuned more to the needs of the users and give the average Facebook user a compelling enough reason to move their online social activities from one site to the other.

And, irrespective of which site wins the battle, the real winner will be the end users as the battle will spur greater innovation.

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