How do I see a graph of a user's total reputation over time?
On Meta.SE, click on a user's name to get to their profile page, then click on Network profile button in the top right:
On all other Stack Exchange sites, click the Profiles button and a drop down list will appear, where you can select Network profile as well:
This brings you to their global Stack Exchange profile. From there, click on the reputation tab, and you'll get a graph of the user's total reputation over time. For example, here's yours:
If you need just your own graph (logged in), there is a shorter way, directly available on any SE site at one click. Just click the mouse middle button over the "recent achievements" icon: (trophy)
You can also [right-click --> open link in a new ...] if you do not have the middle button of the mouse.
If you need the full graph over the full time of another user, there is no other way than the one of the other answer.
This also delivers the user ID in the URL which you need to get your view / score question stats downloaded as csv, see here. Such question stats are a nice complement to the curve when downloaded several times over time since question views are not stored. The stats are updated every Sunday.
You can also get a graph over time using SEDE, meaning a query against the SE database, see here. But then you need the user id of the profile of each community site to give you a detailed graph, while this question is about getting a full overview. Example from the link:
For example, to get this for Stack Overflow, go to your profile page and copy the user id of that Stack Exchange. Query it and click on the graph tab. (Credits go to the comment at How to get a bigger reputation graph?.)
You could still get the detailed graph of all of your sites in just one graph, but then you would have to run the query on each of your profiles at first, then put the data in one table, and then make your own graph of it with a program of your choice.