how to revoke gmail access to blippr account?

We use Google's secure authentication system, so you never enter your Gmail password on blippr. Rather, Google authenticates you, then gives blippr a special token (think of it like a password specifically for blippr to talk to your Gmail) with which to access your address book, so we never have the "keys the the kingdom". This is a system known as "OAuth", and it's pretty cool. We're working to implement it across as many services as support it. :)

To revoke blippr's access to your Gmail address book, simply go to https://www.google.com/accounts/Issue... and revoke any of the access tokens you would like.

Edit: If you mean that you signed up using your Google credentials as your blippr account, that's changeable too. Go to http://www.blippr.com/home/edit and you can change your email address or password associated with your account.

If you're concerned about the security of your password, it is stored as a one-way salted hash, so it's not recoverable and can't be pulled back out of the database. We also use SSL encryption on any page that asks for a password, to ensure that the transaction is fully secure and your credentials are as safe as we can make them.