Use controls to see different aspects of the sc2 ladder ranking history. Seasons are marked by the colored sections of the x-axis. Mouse over on points to see date, season and full information for that point.
The other data selections are pretty straightforward (world, region and league rankings) but active needs a longer description. The purpose of this site is to track progress by tracking rankings over time in a more stable way than using leagues. But players stops playing and a few new are added making the region rank comparison flawed. To make another flawed way to track progress, ranking history among "currently active" players was added. If selecting "Data: Active" region rank will be shown but all values (region count and region rank) has been calculated by only using the intersection between the currently ranked player base and the ranked player base at the time of that point.
There is no selection available between HotS and WoL. For each point in time HotS or WoL data is chosen based on availability. HotS data will be selected before WoL data. So for example if the team was ranked in a HotS ladder the HotS data will be shown. If there is no HotS data available but the team is ranked in a WoL ladder the WoL data will be shown. If a team has switched from WoL to HotS between seasons both HotS and WoL points will be shown in the graph (but only one for each point in time). Mouse over the graph to see if the point is WoL or HotS.