Interpreting Dev Stats: Superimpose site-wide trends over data

My roommate and I were looking at my data, and he had an interesting idea that would help with interpreting data. Above is my daily visits, and you can see two spikes on the two weekends. The second spike is significantly lower than the first, and I want to know why.

There are two possibilities that I can think of:
[li]After the initial surge of players, some players got bored of the game and stopped playing.[/li]
[li]The first weekend was at the end of the summer and school mostly wasn’t in yet, so there were more players available at that time than on the second weekend.[/li]

The answer is most likely some combination of these, but to what extent? To concretely know, if sitewide stats for all games were scaled and overlaid over my data, I could see how my game is matching up to the playerbase on the whole. If my stats stay on track with the global stats, it would mean that my game is stable, and any fluctuation can be known to be due to a global shift in players(it’s a weekend/holiday/change in season). Conversely, if my stats fall below the global curve, I know there is an issue local to my game(players are getting bored, or everything broke so players are leaving), and if my stats rise above the global curve, I can see that my stats are improving.