Google is alright but I wouldn't say it is the best for business. If you are looking for a professional social network for business then I would recommend LinkedIn. Anyway, you can tell someone has blocked you from Google Plus if you see a restricted button somewhere on the page. read more
Know When Someone Removes you From Their Google Plus Circles with GoogleMinus. FYI, this is what happens when you block a person in Google’s social network. You can’t see his content in your stream. That person won’t be able to comment on your content. He will be removed from your circles and extended circles. And that person can’t see your public posts. To Unblock a blocked person in Google+. 1. Sign into Google plus with your email and password . 2. read more