That's how to check rankings online with the Steam client.
1. Access the community page
2. Select "Rankings" from "Show Data" in the top right of the "All" tab page
3. Select the ranking you want to check from the play data page
4. You can switch the display from the pull-down menu.
*Note
The data displayed for each ranking is taken from the in-game score and is uniformly divided by 1/10.
This is to avoid the limit on the number of digits that can be displayed for Steam rankings.