Google Analytics is not a direct part of Weebly but rather it is a tool that can be added to your Weebly blog through script. Google Analytics is a very versatile tool that I have only begun to explore it tracks how many viewers are unique to your site, how many times viewers have returned to your site, what countries your viewers are from and it also allows you to see how long the average reader spends on your blog. These functions are the functions that I was looking for in order to better understand my readers. I am loving this tool so far but don't take these functions as this tools limitations.
One word of advice with Google Analytics is that this tool takes about a day to activate so don't waste your time like I did by repeatedly deleting and re-adding the code until it works...it will work you just need a little bit of patience! Also, from my understanding, you need a Google account to access this tool and you can access the tool through logging in to the Google Analytics page itself not through Weebly. If you have any questions, please comment and I will get back to you as soon as I can!