It's hard to say for sure. They might be rethinking their strategy or have run into financial constraints that have halted new comic production for the time being.
I have no clear idea. It might have changed its business model and didn't work out as planned, or there could have been legal or copyright problems that affected it.
I'm not 100% certain. You might want to look at its privacy policy, the kind of content it offers, and whether it's been flagged by security software. That could give you a better idea of its safety.