Google Hangouts vs iMessage

Google Hangouts
Google Hangouts is a live video chat app. It allows to share your screen, collaboratively draw on a whiteboard, edit Google Docs documents, create broadcasts for the unlimited number of viewers. Splitted into group chat app and videoconferencing app. Secure Google Hangouts alternatives are Signal and Telegram.
iMessage lets you send messages back and forth with anyone on iPad, iPhone, iPod touch, or a Mac. If you’re a texter, you’ll love Messages on iPhone, iPad, and iPod touch. Now they all come with iMessage, a service that’s an even better kind of texting. Because it’s free for you and anyone texting over Wi-Fi using an iOS device or Mac with iMessage.

2011 - Google+ launched pages for companies and brands to strike back at iMessage

Google Hangouts for brands
After Google opened its social network Google+ for Google Apps business users, it didn't make enterprises waiting for a long time with the next step. Today it added an opportunity to create pages for companies and brands, like on Facebook. Many companies have already done it. Here are examples of business pages: Toyota, Pepsi, FC Barcelona, Angry Birds. And though it's not possible to select vanity URLs yet, spend 5 minutes and create a page for your company right now. You can do it here: Company page in a social network - is a great way to make your business closer to your customers and partners (and to find new ones). Of course, meanwhile the Google + Pages are less functional than Facebook Pages: you can't publish RSS-feed, only one person can add messages, widgets for websites and apps are not ready yet. But there are two major benefits.

The first - is of course the video chat Google+ Hangouts, which lets you organize webinars and other meetings with clients on your page.

The second is called Direct Connect. It's a Google's secret weapon, which Facebook can't beat. It allows to find Google+ pages right in the Google's general Search, by typing "+" in front of the search query (e.g. "+ Pepsi"). And that, potentially, is a powerfull marketing channel.