A while ago I noted that Wikipedia was including "permalinks" to their articles: a way to refer to the specific version one was reading. The citations standards for Wikipedia had also been updated and recommended that people use these versioned links as well as specific date and time stamps (UTC) to refer to articles. Last week I implemented this for my own references and went through and updated the 80 or so Wikipedia pages in my Mindmap to make sure that any excerpted text was from a specific and dated page. At first, I thought this level of specificity wouldn't be required, but in fact, I did encounter a couple of cases where text I had cited was no longer present in the most recent version.
As an aside, a neat feature of my reference system is that it is quite easy to query for titles that have been read in a certain period. For example, to see everything I read last month, I just need to query
r=200503". Creating a RSS feed of what I'm reading would be an easy next step!