This idea came from Grant Scott and Neale James, and it’s to treat your camera as a sketch pad rather than every shot being a finished and polished masterpiece. This means that photos become captured ideas for future development or (the shame!) simply a record of who you were with and where you were.
This is easy with digital but was harder and more expensive when I used film exclusively. With the marginal cost of a digital picture being effectively zero, why not grab pictures of things that are interesting or have possibility? It can also be an informal record of where you were or what you were doing. If your camera can also capture the location of a picture, you have the easiest method for grabbing something interesting and then finding your way back to the place at a better time or in better light.
I think this also fits with the idea of journaling. This is keeping a written (and doodled) record of your thoughts and ideas. Ade of the Sunny 16 podcast is doing this. Even I do it. I carry a little notebook that fits in my pocket and one of those little space pens. I’ve also got my favourite little snapshot camera that isn’t much bigger than the notebook. This goes in the pocket or the bag and is part of the leaving the house checklist (keys, wallet, phone, poo bags for dog, camera). The notebook captures stuff for later – ideas, plans, books to read, films to see, even ideas for pictures. The little camera grabs things as they happen – sunrise, newts on the path, details of cameras to use in this blog. The notebook jottings get reviewed and either moved to a collection (books to read), turned into something useful (ideas to try) or deleted (jobs done). Same with the camera – the pictures get moved to the filing system so that I can find them again or deleted if they were a temporary record.
The benefits are in peace of mind. I forget less, like ideas or references. I remember more, like things that caught my attention. There is another benefit in having the recording tools with you. It’s less stressful than seeing something and having nothing to save it on or with. Turning these things into a habit means that I’ve always got them with me, so I use them.
An aside – I’ve also got a notebook for the house. It has a plan with measurements of every room, how much paint or wallpaper it took and the names of the paint. It gets updated when we move and is most excellent for decorating, redecorating or choosing furniture that fits </smug>.
I know a mobile phone can do these tricks, challenging the need to carry a separate notebook or camera. I do find though that the pictures on my phone rarely make the jump to my main picture files so I lose track of what I’ve got. I also find it easier to make notes on paper than in a phone, because I doodle shapes with the words. Or maybe I’m a dinosaur and still can’t work my own TV. Taking written notes does mean though that I can use Easy Script shorthand for speed, compactness and a basic level of privacy.
Anyhow, it’s the idea I recommend, not the method. Capturing notes, thoughts and pictures as they arise so that you can reflect on them later is useful. It also breaks the psychological bond that everything you do must be at least good, if not perfect. Unfinished means still flexible and capable of development.
Fup Duck Photography 
I’ve definitely used my cameras as sketch books. (And I use my sketch books as sketch books!) I think you can still do it with film, too. This is where a half-frame camera excels. When I use my Olympus Pen EES-2 I’m less worried that all my shots are “perfect”.
Good point. I had a Pen EE and it was perfect for guilt-free experimentation. I do like my little digital job though, as it can do macro and has a zoom.