Please remember that PassingPix.com is still in beta

Technical

Can I login from multiple devices at the same time?

Yes. By using 'resource-IDs' you can be logged-in from 3 different devices at the same time.
It doesn't matter if those are different browsers on the same device or different devices altogether like your laptop, mobile phone and PC at your workplace.

A resource-ID is a number ranging from 1 to 3. It needs to be appended to your E-mail address, separated by a hash ('#'), when logging in.
e.g. me@example.com#1

If you omit the resource-ID, #1 is automatically chosen.

Do I need to enable cookies?

Yes, if you want to log in with your user account.

Do I need to enable JavaScript?

No, not necessarily. Some JavaScript is used here and there to enhance the user interface.
But it is not required for the basic functionality of PassingPix.

Salted hash?

Short answer: A way to compute a value (hash-value) from data so that it can be checked for equality with the original data, but cannot be used to rebuild the original data from the hash-value.

Long answer: Wikipedia: Cryptographic_hash_function and Wikipedia: Salt (cryptography)

Ruby? Python? PHP?

No. Perl.
And yes, I have a long (braided) beard.