A lot of spam email lists are created by bots scraping the web picking up every email they can get their dirty mitts on. Scr.im is a lightweight app that allows you to encrypt your email address as a url, if someone wants to get your email address they just have to click the link and enter a captcha to prove they are human. A very simple solution, to a pervasive problem. The only problem is that most people don’t  realise that this is how spam email lists are often created, so its a problem they aren’t aware of.