The first thing you do when you take a piece of paper is always put the date on it, the month, the day, and where it is. Because every idea that you put on paper is useful to you. By putting the date on it as a habit, when you look for what you wrote down in your notes, you will be desperate to know that it happened in April in 1972 and it was in Paris and already it begins to be useful.
But actual usage is what matters most — consistent, longterm usage. MySpace isn’t struggling because of a lack of accounts; a lot of us still have accounts there, but we’ve stopped using them.