I tried a diary application on the Palm, but it was awkward to use and the Palm is not great for entering lots of text.
Recently I thought that I could do something in email. I spend most of my waking hours in front of a computer and email is convenient. My thought is that I would mail myself, possibly using a dedicated account. Entries would be automatically date sorted. I could even encrypt to prevent anyone else getting at my secret thoughts.
An extension of this would be to then extract the emails and convert them to some easily searchable format.
This is a diary for private thoughts. Anything public can go on here or Multiply.