Can't use anything
I signed up and was immediately caught in an endless loop of "HTTPs (the encrypted version) of Todoist is only avaible for premium users". I couldn't even click through to sign up for Premium if I wanted to, and I haven't been able to try a single feature yet. BTW, using Win7 and Firefox.
Please disable a plugin called "HTTPS Everywhere" or any other plugin which may force an HTTPS connection in your browser.
Aha! Thank you!