With all the money they have I would assume that they are just constantly working on security and making sure everything is up to date with current security protocol.
stamp is not even a pimple on a donkey's but compared to fb, twitter, etc.
Mr. $ofty has over a million servers
Google, who does not report such numbers, is estimated to have more that.
Facebook admits only that they have 'hundreds of thousands' of servers.
You think stamp has 100,00 servers?
When BCT just went down it was because of a hard drive failure. Think about how crazy that is compared to the above.