When I was working on a recent SEO campaign, I felt a certain frustration using seoMoz DA as a metric. It's really only as useful as how everyone else is doing because of how dependent the metric is on the monthly index size, etc. So I created this free tool that allows you to automatically keep track of the domain authority of the domains of any URLs that you would like and any relevant competitors. Feel free to signup and start tracking here. It is completely free. Metrics are updated at the beginning of every month. You can enter multiple URLs at once separated by commas. Everything is still in beta so please come back with any suggestions so we can make this better for everyone. Also, I'm hosting it on my own little DO droplet, so if it goes down please bear with me.