How do you remember programming related stuff? Did you get the feeling you did encounter the error you have now a few years ago and you could swear you knew the cause but now you forgot it?

Did you work with the xsl's string parsing some time ago but now you can't remember exactly which are the string functions altogether from xsl and you have to start from scratch? Or perhaps you forget about some feature from Apache Commons like "filtering a collection by some predicate" that you surely used in the past.

So how do you do it? I tried having a blog but when I develop apps, I never find the time to update the blog or write about my experiences. Also, using a wiki is a nice thing but then I found it difficult to keep a clean separation between them since many times I needed to change a blog post to add new information about that topic. This made me think that I actually should have put this topic in the wiki instead of the blog.

Do you have any systems that help you remember about your programming experience? What's your setup?