Tried to register but got a cryptic "Unable to register using that email address and username". Tried several combinations with no luck. I think it is in some s

Tried to register but got a cryptic "Unable to register using that email address and username". Tried several combinations with no luck. I think it is in some sort of closed beta. Being able to quickly generate a good looking chart that intelligently picks ranges, min, max, etc. and share it with a public URL seems nifty. Are there other similar services that have a pain-free way of doing this sans google sheets?