...
On any of the add/edit pages, this design is quite learnable. It uses a form interface in a way that should be familiar to most internet users. All fields and buttons are clearly labeled with the information they contain or the function they perform. The only exception to this is the task lists, which add or remove items with a button containing "" + or ""-. The meanings of these symbols is are relatively obvious in context, however. Furthermore, the use of "" + or "" - symbols to mean "add" or "remove" is consistent within our task editing pages, and is not uncommon in websites in general.
...
Affordances are appropriate to the function of the components (with the possible exception of the boxes, as described in Learnability). The design is not cluttered, but contains enough text that the user can easily understand what each component is supposed to do.
Perhaps the most problematic visibility aspect of this design is the location of the add buttons on the main page. The bottom of the page is not necessarily the first thing that will capture the user's attention. The design is so simple, however, that this is unlikely to represent any substantial difficulty.