mahesh2k is actually right in his first line;
Anyone can follow any other profile in Google+ and you've no control over who can follow you.
Anyone can view the content that you choose to make publicly available (welcome to the internet!). Where I think he is misinterpreting things is that following someone is not the same as friending on FB (not as a one-way action anyway).
If someone follows you on G+, it means that your public posts will show up in their stream, nothing more. They would be able to see those public posts by going to your profile as well, that is the whole point of "public". There is no relation the other way unless you choose to follow them back.
What they can see is the public parts of your profile and your public posts, which (by definition) anybody can. If you are posting something that you do not want everybody to be able to see, don't share it with everybody, share it with your circles.
If you choose to block them, it means that you will never get any posts from them if they try to share something with you, they cannot comment on your posts -- they can't even +mention you.