Can we setup a catchall email address that accepts issues from anyone?
Sifter does not support catchall email addresses as it's designed to be an entirely internal tool, and everyone that uses it must explicitly be granted access. This kind of functionality is generally reserved for a help desk rather than an issue tracker.
The simplest way to think of it is that not all support requests require creating issues. For instance, a customer may have a question about how to use a feature. This support request requires a simple answer, but it doesn't require any developers to be involved or code to be changed. In our experience, it works better if your support requests aren't intermingled with your team's bugs and issues. If a support request turns out to be a bug, that bug can always be logged in your issue tracker separately, but the amount of support requests that lead to logging issues will generally be fairly small.
If you need to support public catchall email addresses, we suggest looking into help desk software rather than an issue tracker. There are a lot of great apps out there, and we've assembled a short list to help you get on track...