After the outbreak of blogs I don't know if anyone is still keeping one of those old-style diaries in moleskin notebooks. In case you're one of them, here's a little piece of software that may be of interest.
iDailyDiary lets you keep a personal diary on your computer, which certainly adds quite a few advantages to the traditional paper notebook. First – and most obvious – you save trees. Plus you can take your diary anywhere with you on a small USB key, even if you've been writing it for years.
Besides protecting the environment, iDailyDiary is also safer, because it encrypts and password-protects your texts. It is also easier to use: you can have multiple tabbed pages for each day, browse through your diary with a handy calendar on the bottom bar and also search for any given text in just two clicks.
iDailyDiary supports rich text, which means you can insert bold, italics and the likes, plus images, web links and other eye candy. This functionality is not perfect though. For example, I found text font selection a bit annoying, as the drop-down menu doesn't show how each font looks like before applying it to the text. Also, images can't be properly aligned to text.
In spite of these flaws, iDailyDiary is still a handy electronic support for your personal diary.