[LaGrange]

Because Google spins things better.

Google has a nerd-friendly message, and produces things that are building dependence and are genuinely useful (like, say, gMail). So, people are less scared of it, and after some time denial kicks in.

Also, I'm bitter because Google is the one software company that I'm scared of more than of Facebook :-D

[Joakal]

For Gmail, you can withdraw your emails out via IMAP/POP. You can export your contacts.

[LaGrange]

Of course you can. But then you'd be also abandoning the workflow, and I meant dependance on that. Only relatively recently mail clients supporting a workflow similar to Gmail show up.