Disclaimer: I don't think TR is receiving monetary compensation from Google or anyone else besides its displayed advertisers. With that out of the way, ...
I don't think Google would have invited anyone they thought would cast the product in a negative light. It's impossible to guarantee 100% approval, but they can target the beta testers for best anticipated responses; they've certainly got the data to mine. Google may be conducting beta testing, but it's clearly also running a campaign of marketing by word of mouth. 'We've seen the Emperor's new clothes and we're telling you they're magnificent! Just you wait; in the meantime we'll hype them some more!'
Lack of an invite makes it impossible to effectively evaluate the product or respond to the chosen; all the average schmoe can do is take the word of the hand-picked. Despite that handicap, I'll tackle Kevin's points. I don't know the adoption rate or market penetration of Google Apps, but I'll bet few on the Fortune 500 are using them as their exclusive business apps suite. Leveraging Plus's interaction with Google Apps won't matter to them. In particular, I'll bet Google's e-mail system isn't their primary e-mail system. That means they'll continue to rely on the contacts management in their selected e-mail system. As to businesses building 'Pages', those may not come at the expense of Facebook. Businesses will target their social interaction to the biggest crowds, and it's too early to lump Facebook in with MySpace. Consumers have a lot of time invested in their Facebook presence, and apparently the majority of them are unconcerned with FB's security issues.
Speaking of beta testers, Google is notorious for leaving new apps in beta for extended periods. I don't see any business adopting a tool to the point of reliance while the vendor can claim it's still not ready.
Finally, exactly how is the name of this service supposed to be written / typed? Is it 'Google+', 'Google +', or 'Google Plus'? I've seen all three used in article here on TR. If the first, it's going to be very easy to overlook the '+' in casual reading.
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