Didn't you ask this question a few years ago?
I do keep a journal - either handwritten in a little book, or in the form of email. Emails are great ... with a 60 wpm typing speed, I can knock of a few days of trip information in no time at all.
The main intent of my journal is to help
me remember what happened on the trip because some of the details can get rather blurry as the years pass. As a secondary thing, the type of journal I keep keeps my family informed of what's going on. I send emails to my parents (and sometimes other family and friends) periodically throughout the trip, and use those emails as a record of what happened on the trip.
After the trip is over, I compile what I've written, trim and edit it, and post it on my website (
www.machka.net), sometimes along with some post tour comments. If someone reads it there and enjoys it, or finds some of my comments helpful, that's great ... but if not, that's OK too because, as mentioned above, my main intent is to keep a record of the trip for my own benefit.
What do I record?
I record distance, because distance interests me, but I won't necessarily include that in my online record. I don't care about time on the bicycle, the speed I travel or other details like that, although if it was an extra long day, I might mention that we started cycling at 8 am and didn't pull into camp until about 8 pm or something like that.
If the weather was something dramatic, and especially if it has some significant effect on the day, I'll record it (i.e. when the temp reached 44C in Queensland; the huge tropical storm that blew through one afternoon; the night it dropped to -6C in the Snowy Mountains and the tent was thick with frost ... etc.) ... otherwise I won't say much about it.
I won't record what I ate unless it had some significance associated with the people we met along the way, or tradition, etc. (i.e. the evening where we were about to have our usual can of beans and couple eggs, when the fishing party sharing the BBQ shed with us noticed what we were eating and insisted on sharing some of their massive quantity of sausages, hamburgers, etc. with us; the cheese selection in France; the Australian hamburgers ... etc.).
And mainly, I will record stories about what I saw along the way, who I met, what I learned, etc. When I write the stories up to post online, I will include links to places, events, etc. that I've come across. These days just about everything is on the internet somewhere. So if I visit a museum, I'll include a link to it on the off chance that someone reading the account might might be interested in further details about that museum.