If you want something fairly advanced (for example you can chart historical changes against multiple URLs), you should check out our tracking tool (can also track historical changes to things like indexes pages in Google, back links, Tweets, Likes, +1s, SERP changes, etc.)... Oh yeah, it's free too. https://tools.digitalpoint.com/tracker
how does this work shawn? Do you put it on one domain, then you can all domains, and all that other stuff too? I thought you had to download, and install, maybe i was wrong...
Nothing you need to download or install. You can track all the domains/URLs you want under the "Links / PageRank / Social" tab. Directly there you can generate individual charts for anything you track. If you want to combine multiple sets of data into a single chart, you can create charts under the "Custom Charts" tab and pick and choose what you want to go on that chart.