Since this is limited to about the length of a tweet and requires to fully trust a third party (Sharelock), why not just send the message directly on Google, Fa

Since this is limited to about the length of a tweet and requires to fully trust a third party (Sharelock), why not just send the message directly on Google, Facebook or Twitter? What is Sharelock adding here other than a false sense of security? Are we supposed to trust Sharelock more than the aforementioned services?