Google+, the company's recently introduced set of social communication services, briefly opened to new participants last night, between about 7pm PDT and 9:40pm PDT. Google engineering director David Besbris, in a Google+ post, said that the Google+ field trial is going well and that Google is seeking to double the undisclosed size of the field trial.

Toward that end, Google provided participants with the ability to invite friends to the closed test of the service. A few hours later, the invitation icon was removed.

Google's business customers, specifically users of Google Apps, have to wait a bit longer to try Google+. The Google Profiles service, a required component of Google+, has not been compatible with Google Apps for several months. Google engineers are working to remedy the situation but there are significant hurdles to overcome, particularly while Google+ is still working through various privacy issues.

"Right now, we're very much focused on optimizing for the consumer experience," said Google product manager Christian Oestlien in a video update. "But we have a great team of engineers building a similarly optimized business experience for Google+."

Oestlien said that Google hopes to make its social networking service available to businesses later this year. "It will include things like rich analytics, and the ability to connect [a Google+] identity to other parts of Google that businesses might use on a daily basis, like AdWords."

Oestlien asked businesses not to create consumer Profiles for Google+ in the interim.

Google will be admitting a small group of businesses into a Google+ pilot test to see how users interact with commercial brand Profiles through the various Google+ services, like Circles and Hangouts. Organizations interested in participating in the test should fill out this Web form, which Google has only publicized in a video shared among those already admitted to Google+.

Oestlien's request comes too late for some businesses, like Ford Motor Company, which has already embraced Google+. On Thursday, Ford hosted a live chat with Matt Van Dyke, director of marketing communications for the auto company, and encouraged Google+ users to visit a Hangout, a multi-person video chat room, after the presentation.

On Monday, Ford Europe launched what may have been the first attempt at social marketing on Google+, a contest to write the best caption for an image, with the winner determined by the number of +1 votes. The contest garnered more than 80 comments, from which a winner was chosen and awarded the Xbox 360 game Dirt 3.

Yet, Ford is still figuring out how businesses fit into Google's social landscape. In a post on Wednesday, the company said, "We're experimenting on Google+ and we've seen comments, both pro and con, about our presence. What would you like to see from us, in order to get the most value from interacting?"

That's a question a lot of businesses are asking both internally and externally, not just about Google+ but about Facebook and other social networks. Are businesses "friends" or something else?

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