Well they don't tell you if they blocked you obviously, because it's a concern of privacy, but you would know if they blocked you if you sent a message or something like that and then if there's no response after a long time, then you know that they blocked you. :P
For Google talk read this: http://www.rakshitk.com/blog/2008/01/26/how-to-check-if-someone-has-blocked-you-on-google-talk/ For MSN go here and read: http://www.mess.be/msnmessengerfaq/idx/0/002/article/Can_you_see_who_blocked_you_on_MSN_Messenger.html
It was replaced by Google Plus. As far as I know, it's not coming back.
no idea.I know this is not informative. Sorry.
They will not know you blocked them.
no
If you are not able to use your account. You might be blocked by Google from Gmail. It can happen if you mistakenly broke any law or regulation.
If you know their log in details.
I would say you are blocked. Quit calling.
No . he would be unable to know that you have block him.
i know this isn't the answer you are looking for but only Google can reveal that and unless someone from Google answers this you cant know
well my sister saw me looking at pictures on google on my ipod touch and she blocked it i dont know how to do it if anyone knows tell me please!
When someone has blocked you from their Facebook, you won't be able to know if they have also deleted you.