Ok, essentially the heartbleed bug was that openssl library was not checking the actual size of heartbeat request and was responding with an extra data giving out some memory junks trying to keep its answer of the same size as the initial request.
Did it related only to users who got authorized on a website or any malicious user having no account on that service and knowing no passwords could start fumbling? In other words do the actual users of a service had wider possibilities to use this bug than others?