I had a journal on v3. I have a journal now. I've kept a diary or journal of some sort my entire life. I was never good at updating it every day. The journal I have at deadjournals hasn't been touched in about half a year or longer.
But my journal here, I try to write at least something everyday, whether it's just a thought of the moment, something that happened during the day, or just a few words about something that's been bothering me.
And as speckieweckie said earlier, you can make any entry you want to "private" so the general membership reading your journal cannot see that entry.
I recommend a journal for everyone