A very timely article, indeed, Phil. I, unfortunately, have to have a whole lot of stuff open on my screen all at the same time because not only do I have my work to do but I have things open in the process of helping other people. I sometimes can't even remember which screen(s) I was on for my stuff.
And, to your point about snippets and larger solutions, I try to keep things in a single directory with multiple subject or technique oriented sub-folders but it's a daunting task to sometime find things and, as you say, even remember that I've once solved the problem and saved code for it. Every once in a while while search for a snippet of code, I'll run across a title in my files that I just don't recognize. Since the files are also named after the purpose or technique, it stops me in my tracks when I see something interesting that I don't remember doing anything with. I open it and, sure enough, I wrote it and I keep saying to myself (especially yesterday) that there must be a better way but, like you I've found that (much like the internet), you can't always find what you need until by accident sometimes months later.
You're article is great because it lets me know that I'm not alone in having this problem.