In my job I deal with several projects at the same time (and who doesn't?). Sometimes I have to make changes to a project which I dealt with half a year ago or even longer. And it's hard to recollect the details about the project. I usually look for the modification dates of the files, then I start digging into my email to find the relevant conversations. If the project is really small then it's not even in company's VCS. Sometimes it takes much longer to recollect the details of the project than to make the required change. I started using Onenote to keep track of relevant information about projects but I didn't succeed much in this, probably because I don't have a clear picture of how this knowledge base should look like.
It would be nice if I can use some automated tool which can connect relevant emails, source codes, bugs information and feature requests and time periods of different activities related to a particular project. With advanced search capabilities.
How do you keep track of this information?