In Outlook Notes are obscure colored rectangles with fancy fonts. (Bear with me, this is going somewhere.) Full text search (Windows Desktop Search in my case) makes them surprisingly useful, but most people (foolishly) ignore them. They have Categories (tags: many-to-many relationship) and data attributes that support some useful queries.
Outlook Tasks, on the other hand, are fancy with RTF bodies that can act as containers for all kinds of things.
Notes and Tasks in OS X are very different. They're especially different in 10.5, where they reflect from Mail.app into Gmail to they live as email messages!
Web 2.0: Howto : use google's imap and mail application as GTD tool
Apple's mail.app features it in the latest version that is shipped with Leopard (OSX 10.5). If you set it up to talk to gmail using imap, notes and todo's are created on the imapserver....
...A todo created here shows up...
... if you go to gmail, you'll see a label (as google calls it) with the name Apple Mail To Do, and if you click on it your todo is sitting right there for you to be handled. As it is all in iCal format, easy calendar integration is there, but most important is the fact that you have access to your todo list from anywhere....
The Gmail integration is completely unexpected and thus far seems pretty pointless (maybe that will change June 9th?).
More to the point, OS X Notes/Tasks are almost the mirror image of Outlook Notes/Tasks. In OS X 10.5 tasks are very simple things -- a single line, a priority and due date, and a status field. Notes, on the other hand, can have many associated tasks and support attachments and (clumsy) RTF editing.
In Claris Organizer (later Palm Desktop for OS X), Notes were distinct entities that could be related to other items.
So you might think you were attaching a comment to an Address Book entry, but in reality you were creating a "note" item and a link from the Address book entry to the note item:
TidBITS Moving Back to the (Palm) Desktop (1999)
Attached to Attachments -- If you've synchronized your Palm device's data and played with Palm Desktop a bit, you've no doubt run into one of the bigger brain-twisting elements of the new Palm Desktop. What happened to attached notes? Under the Palm OS, you can create a note ... that includes miscellaneous information... Looking at the Note List for the first time can produce a moment of organizational panic: in addition to the records you entered in the Palm's Memo Pad, you'll find dozens of records marked "HandHeld Note:" then the name of one of the Palm's built-in applications...
OS X 10.5 Tasks and Notes have something in common with this, though the user interface is pretty different (much simpler basically). If you start out creating an OS X Task I don't think you can create a Note related to it, but if you instead create a Note, then transform a row (line item) into a Task, you're creating a (hidden) link to a new Task item.
The awkward Palm PDA/Claris Organizer PIM integration resembles Apple's peculiar Gmail "integration", and foreshadows how hard it will be for the iPhone to sync with both Outlook and iCal. (Maybe that has something to do with why Apple hasn't put tasks on the iPhone!). I presume one would have to sync an Outlook Task with an OS X Note that happened to contain a single task!
Software dies, but software memes (and synchronization problems!) live a lot longer.
So it seems OS X 10.5 Mail.app is slowly turning into a simpler version of Outlook -- now with email, tasks, calendaring (ok, via iCal) and notes.
Meanwhile Google Apps is turning into a Sharepoint clone.
It's sure going be interesting to see how this all plays out with the iPhone.