I simply find it amusing that everyone is so desperate to get into Google+ that they are willing to give their email addresses to complete strangers on twitter and the many online forums out there.
Yes, I agree that they seem to have really captured how humans interact with each other (I didn't get in yet, so I don't have first hand experience).
Yes, I agree that Facebook is really pushing it when it comes to privacy.
Has everyone suddenly forgotten about businesses that collect email addresses to send spam? What about burglars that used Facebook status to see which houses to rob?
So, the person is part of your "professional group" on LinkedIn; that doesn't necessarily mean that those are real live human beings that actually work for companies that exists.
LinkedIn has had problems in the past from what appears to be real people posting the same "discussion" topic to promote their "services".
Honestly, they're so bad that they don't even bother to make sure that they don't post the same "blog post" on the same group on the same day.
So, let's review the basics:
First, if you don't know the person asking to be your "friend" on a social networking service, it's probably best to ignore them.
Second, it's probably a good idea to review your "friend list", followers, etc, and take out people that you don't interact with on a regular basis--especially if you use your cell phone to post updates.
Lastly, for goodness sakes, don't just give out your email address to random people that dangles a carrot in your face.
Cross-posted from Home+Power