Well, it will be no surprise to those of you who are GTD fans that I am a firm believer in writing things down. For me, the real purpose is less to "get stuff out of my mind" and more to help retain and recall things I want or need.
At a recent conference I heard a speaker reference Confucius saying that "The strongest mind is no comparison to the weakest ink". In other words, memory is faulty and short term, the written record has longevity and can be recalled and accessed by other people. I used to rely on my memory for many important things, but as David and others have demonstrated, that simply clouds up an instrument that was built for rapid processing, not long term storage and recall.
So, how do I recommend you capture and recall stuff that you record? Use all the tools at your disposal.
First, when I hear about a book or record that I think might be interesting, I add it to a wish list on Amazon. It's not that I necessary will purchase the book or recording through Amazon, just that it is an easily accessible list that I can "carry" with me anywhere.
Important meetings, dates and other information goes on a virtual calendar, whether that's Google Calendar or an Outlook Calendar. These calendars are consistently synched to the spouse's off-line calendar on the refrigerator at home.
Topics I'd like to write about or explore in more depth go into Blogger or Typepad as draft posts. I usually keep three or four ideas percolating in both Blogger and Typepad before publishing them, to see if there's more to write and to offer. I find it helpful to return to these ideas several times, and the fact that they are on the web makes them easily accessible.
Email - I'm now one of those guys who is squirreled away in the corner using the latest device to receive and respond to email. In one regard, having mobile email at my fingertips makes it easy to assign a quick "to do" or even record ideas or suggestions. I am learning to channel or ignore the inbound stuff and consider it during certain periods of the day.
Project work - I've found the thumb drive to be one of my new best friends. A thumb drive is exceptionally helpful when working with clients when I cannot attach to their network. We can easily share documents and I can carry that document with me in my backpack or pocket, so there are now times I travel without a PC.
To Do lists. I am locked into the habit of creating to do lists, and I still prefer pen and paper to do this. There's something about putting the pen to paper that allows time to think and reflect on the day ahead. I capture my to do lists and carry actions forward that I don't complete. As may of my co-workers could tell you, I have a stack of these old to do lists that I can refer to when I need to look backwards at the work I've completed or issues I've encountered in the past.
Clearly, there exist a number of tools that enable us to write things down, and a reasonable filing system will make it easy to find and sort these ideas and concepts. However, there is still a broad distribution of these things we write - spread out in mobile email, thumb drives, blog sites and so forth. I'm still waiting for a virtual content manager that understands I want to create "content" and then determine how or where to deploy that content - as a word document, email, to do list or blog post.