Some promising applications to provide statistics (eg
"Who has viewed your profile", "who has blocked you", "who is your biggest
admirer ", etc..), to allow you access to offensive content,
or even to avoid losing a specific function of Facebook (for
example, "get a old profile", "confirm that the account is active,"
etc..) need to stick a Java script in the user's browser.
Once in the browser, the code can access the controls Facebook
with the privileges of the user and he will release this scam using
APIs like Facebook messages, invitations and mailings
messages on the wall of Friends