Google Plus vs LinkedIn

Google Plus
Google+ (Google Plus) is a social networking and identity service. It's as a "social layer" that enhances many of Google online properties, and that it is not simply a social networking website, but also an authorship tool that associates web-content directly with its owner/author. Google+ users are interacting socially with Google+'s enhanced properties, like Gmail, +1 button, and YouTube comments.
LinkedIn is a business-oriented social networking service. 250 million+ members. Manage your professional identity. Build and engage with your professional network. Access knowledge, insights and opportunities.
Face to face in the news:

2013 - LinkedIn wants to become contact manager in every Email client to win over Google Plus

Most people are moving away from e-mail as a tool for communication with family and friends. They use social networks or skype. But in businesses, especially for communication with partners and customers, Email continues to be probably the main communication channel. That's why, LinkedIn (the social network for business) sees the great prospects for itself in this technology. Ideally, LinkedIn wants to become an address book in each email-client. Address book, which contains the most recent and complete information about your business contacts. For this reason last year LinkedIn acquired the browser plug-in Rapportive, which works inside GMail and shows the social profile of a person that sent you email. Rapportive is still working, and recently LinkedIn introduced its version for iPhone mail - LinkedIn Intro. This is not a standalone app but also a plug-in that is registered online and appears in the phone settings. The video above shows how it works.

2011 - Google+ opens for Google Apps users to keep up with LinkedIn

Google Plus Google Apps
One advantage of Google's main advantages over Facebook is that the search giant can perfectly integrate businesses and individual users (clients) in the single network (Google +). And if it succeed, Google+ will become the successful platform for advertising, unlike Facebook, which hasn't achieved the significant progress in the advertising incomes yet. The first big step in this direction has been done by Google today: from now Google Apps Now users can log in to Google+ under their corporate accounts and use Google+ for business needs. First, Google+ can serve as a social layer via creation of business/project groups (circles) with employee profiles. Second, it can be used as an intranet microblogging system for discussions and file sharing (like Chatter, Yammer ...). Third, it allows to search and support customers via Google+. But of course, the killer Google+ for business is its video chat app Google Hangouts.

Because after the recent update Google Hangouts allows to video chat (with up to 9 people) collaborate on Google Docs documents in real time, share screen, collaboratively draw on the whiteboard and organize webinars. And it's all for free.