GettingThingsDone afficionadoes, let's face it, are often geeks. And GTD afficionadoes who read wiki are almost always geeks. When geeks approach GTD their very first thought is, ''paper? folders? WTF? I'll just use <PIM of choice/>''. But the sad fact is most PIMs do '''not''' adapt well to implementing GTD without a lot of hacking. So begins the great quest to find the perfect GettingThingsDoneSystems for you.

The essential elements of GettingThingsDoneSystems are:
* An Inbox. You might already have one of these ... but this is isn't just an inbox for your mail. It's an inbox for all things you have in your head. Typically these are actions you need to process.
* A collection of Projects - each an ordered list of Actions - things to do.
* Maybe/Someday - a list of Actions you may or may not get around to in the fullness of time.
* A collection of Contexts - each an unordered list of actions collected according to the way you do things. For example phone calls, computer work, errands ... typically you have a dozen or less ways to do things.
* Next Actions - a collection of just the next actions you need to do for all your projects, typically sorted by Context.
* The tickler file - a collection of date-ordered ToDo''''''s that tickle into your Next Actions as you move through time.

This page gathers descriptions of the systems people on wiki are using. Anyone else's choices almost certainly won't work for you. But they may give you ideas. Please add your experience in a separate section below.
----
PeterMerel: I tried using TiddlyWiki for GTD (d3 and monkeyGTD) but then a colleague showed me how he used a windows outlook plugin to integrate email into his system ... and then I knew I was only HalfwayToHappy. It took a couple of days of evaluating all possible alternatives before settling on this SimplestThingThatCouldPossiblyWork for GettingThingsDone on MacOsx:
* Mail.app Inbox as Inbox
* Mail.app Drafts as Maybe/Someday
* MailTags Keywords -> Mail.app folders as Projects. Sort these by MailTags due-date for order.
* MailTags "Projects" -> ICal calendars as Contexts
* ICal ToDo entries as Actions
* MailTags to assign Actions to Contexts and to attach the mail item URL to each Action.
* HighPriority to put the Next Actions per Context right on the desktop
* Ical ToDo''''''s with due dates as the tickler file; HighPriority filtering stops these polluting today's Next Actions

Advantages: 
* Automatic calendar syncing and sharing per ExtremeGtd, and to your PDA/Phone/iPod. 
* Much less rinky-dink than kGTD.
* Intimately integrated with email.
* Unifies ticklers with project order thereby eliminating a redundant 43 folders.
* The related plugin "Mail Act On" by the same developer as MailTags provides rapid Inbox triage.

Disadvantages:
* Using ToDo due-dates for project order means you can't re-order a project by dragging and dropping. Tolerable.
----
Others?
----
TarynEast:
Hmmm... looks interesting - but I like being able to sort my projects however I like. Don't forget that GTD states that if you have only 50 projects you haven't been trying hard enough ;)
Which means ability to categorise and sort becomes paramount!

''I can categorize projects and context fine. I agree that mixing tickler order with project action order is non-standard. I'm hoping that the Leopard Mail.app which integrates ToDo''''''s will provide a better way. But for now I'm very content.''

I also don't find that I use the calendar integration very much - there is so little that I do that is HardLandscape.

''I didn't grok ticklers at all under tiddly. I knew I needed some kind of calendar integration but the reminders thing never did anything without me going and looking at it. Which I didn't. Under the setup above my ticklers automatically become Next Actions as the day ticks over.''

How do you see the mapping between iCal calendars and Contexts?

''ICal provides multiple calendars, each with its own ToDo''''''s. So I name these @calls, @reply, etc. Undated ToDos or ToDos with a due date earlier than tomorrow simply float to the top. I do see a few more of these than I would if I had ordered Projects. But so far I don't mind that.''

I also very much like the TiddlyWiki's handling of NextAction lists and contexts (ie multiple ways of getting to the same data). But there are definitely limitations to that system too.

''What tiddly lacks is the email integration. I'm coming to find that indispensible.''

I've noticed that the recent upgrades to the d3 wiki are pretty good (defer function and "important" flag for projects). I'd still like to be able to do heirarchical projects - which doesn't seem a part of that system. I'd also like "waiting/blocked" to be a flag on an action,  rather than a context - so that when you click it off - it returns to its previous context.

''I think I disagree; waiting is a way of dealing with an Action.''
----

I practice GTD using EverNote, following the great guidelines in this article: http://www.40tech.com/2009/08/25/getting-things-done-gtd-in-evernote-with-only-one-notebook/

It wouldn't have occured to me to use EverNote in this way, so far I'm loving it.