We know it makes some uncomfortable to have the credentials in the cloud, but we felt it was important to make it as easy as possible for people to be able to use any device (we're working on iOS and Android) to access all of their email accounts. Of course it's up to you to decide if you trust us, but we've went to great lengths to make sure your emails don't pass through our servers and to keep your credentials secure. We explain our security precautions on our FAQ, which we'll continue to enhance going forward.