I probably ought to have thought of that myself. In particular, an LJ entry is dated, which implicitly suggests that keeping it permanently up-to-date is probably not on the cards. I think part of my worry is that if I post (say) the traffic-lights thing on the web then I might feel an ongoing compulsion to maintain it, making additions and corrections in response to readers' comments. Posting on LJ would neatly get around that effect.

Moreover, you can backdate LJ entries. That way you have them for reference and they're readable to anyone curiously browsing your archives, but they don't intrude on flists or attract too much attention.

Though it would have the disadvantage that people who wanted to be kept up-to-date on new entries couldn't use the friends list feature to do so.

In which case, a separate account (whether personal or -- for ease of posting without logging out -- a [closed] community) might be better.

ease of posting without logging out

There's a "post as a different user" button. It has the disadvantage that you can't choose an icon, but that's about it.

Alternatively, LJ clients such as logjam...