Keeping up-to-date

During a recent advanced web searching workshop I tried to demonstrate Yahoo! Mindset but the link didn't work. Thinking that I was at fault for not updating my presentation I apologised and later set about trying to find the new link, with no success. I then read on Phil Bradley's weblog that it had disappeared. It was a useful little gadget and I'm sorry to see it go. So many useful links that I have built into presentations have either disappeared altogether or had their urls changed that I would like to stress the importance of checking every link before using it in a presentation or listing it on a handout - unless you don;t mind your audience losing faith in you.