First of all, I was wowed by the design of your app. very good job on that. I created an account and tried out some of the features. The features are great, and I think it can really help people.
Two things I would have liked to see as first time visitor:
1.) More info about what is cal, forcal, withcal, askcal. maybe in novice on planning stuff, but I am still not clear about what the differences are between these.
2.) This is not anything major but I'll give my 2 cents anyways. After signing up and clicking on the activation link, it again tells you to log in. Would be better if that extra step of logging in is avoided. As far as I know, on most sites, you are logged in after sign ups. These little things can potentially put off first timers.
Again, really good job. I'll tuning into plangr again. Don't take my advice as a must do, you clearly have put lot more thoughts into the product you are creating, and I am just a visitor. Just something to keep in mind. I am also trying to get some feedback on an app I am working on. I hope you get more quality feedback and make your already cool app a great success!
take it easy :) -easymode