Originally Posted by Mixalis
Am I doing something wrong?
That looks right to me. That's how I use it with my .Mac address.
One thing that confused me at first was I thought the registered email address needed to be firstname.lastname@example.org. So I tried creating a .Mac email address alias in that format. But the system would tell me that I couldn't use the plus symbol. So I gave up on it and used the "--" method, which always worked well for me.
It wasn't until some time later that I learned that you don't need to have an email address registered with the "+omnifocus". Instead, just use your existing address and append the "+omnifocus" string in your mail application; no special addresses or configuration is needed. Apparently, most email servers ignore any characters after the plus sign and just deliver to the username that precedes it.
Once I tried that, it worked great with .Mac and I switched from using the "--" method and continue using "+omnifocus" to today. Although, I imagine I'll stop using it sometime around July 11th. :)