Company: 
RememberTheMilk is a new ajax-rich to-do list that is similar to 37 Signal’s Ta-Da Lists.
RememberTheMilk lists are organized by tabs. Items are easily entered (although there is an extra click in there that bugs me). Clicking between lists is very straightforward. Items can be easily reordered. And you can also share lists and/or choose to make them public.
One thing RememberTheMilk does very well is to allow lots of metadata to be associated with a single task. Priorities can be set with a nice color-coded system, and there is flexibility in setting done-by dates. You can also add notes to a task.
A really nice feature is the ability to add tasks via email.
Reminders can be sent via email, instant messaging or sms. You can also subscribe to lists via RSS.
Overall, using RememberTheMilk is a much richer experience than Ta-Da Lists. Setting date reminders is particularly useful. However, there is a definite tradeoff in ease-of-use. Using Ta-Da Lists require no training, while I seem to be referring to the RememberTheMilk FAQs constantly to understand functionality.
RememberTheMilk was created by Emily Boyd, Omar Kilani and a stuffed animal named Bob T. Monkey (I prefer live mascots myself). 
I agree about the tradeoff between simplicity and functionality… Unfortunately in this case I opted for simplicity and wanted to cancel my milk account. I went looking to cancel my account only to find that I had to email them a request to do it. Ho humm – I sent the email. 10 seconds later it bounced back. Not so good.
Excellent!
One thing…surfing the web i’ve found this link: http://www.calfeed.com/
Do you think are the same team who developed remeberthemilk? I think, yes!!!
The idea is great, feed your calendar! what do you think?
Was about to reply to “although for some reason they do not provide RSS feeds for lists, which is crazy.” But I see you changed it!
In my opinion, RememberTheMilk knocks the socks off TadaList… You’re right, there are a couple of places that are not 100% intuitive, but the app is MUCH richer. If only I could have the page creation of Backpack or Zoho with the ToDo lists of RememberTheMilk!
several surprises. When you go to type in contact, it tries to be helpful and suggest names of people on the system you don’t even know- then you start to wonder if they can see all your data somehow, of course that is a bit of paranoia. Also, the SMS service looks to be good but how much does it cost? and does it work from other countries- nothing really explained there.