I agree that 3rd party services can be less than ideal, and sometimes really undesirable for some contexts. The reality though, is that people need to communicate these things, whether they be passwords, or tidbits of info that they don't really want to persists. The current way that they do it is via IM or email, which now get logged, stored, indexed, etc. by the client software or middle-man service providers. While we don't expect or recommend that companies put ultra sensitive data into our system (at least, not without strong encryption), we feel it does fill the more common need. We're pleasantly surprised at how many other people agree too.
"the GPL is too restrictive and dogmatic to be usable in many cases"
Does anyone else see the total irony in this? Considering that both Ruby and Git (two of the core technologies GitHub runs on) are both GPL. People can use whatever OSS license they want, I certainly have no gripe with him using the MIT license, but I could do without the dogma.