You can use timeline chart to look at the development of your search field and your selection over the time.
Selecting a Timeframe
See a spike or dip in the timeline? Simply drag and drop your mouse cursor across that part of the visualization to select the timeframe. You will see the selection appear in the selection panel, and the other visualizations as well as the list of Signals will be filtered down accordingly.
To remove the selection, click on the "X" in the selection panel or at the bottom of the timeline visualization itself.
Grouping and Comparing
You can choose a property to group Signals by in order to then compare the development of those groups over time. Currently, you can choose the Signal type (which is selected by default) and the country properties for grouping.
If no selection is active on the chosen property, the top 5 values will be displayed as separate series. If you want to choose which values to compare, just add them to the selection using the according bar chart in the side panel (Or try using the world map visualization for selecting countries!).
Normalizing the Series
By ticking the "Show Series Normalized" checkbox, you can normalize each series by its maximum value during the period defined in the search field.
Why would you want that? Sometimes, the absolute numbers across the groups can differ substantially, making it hard to compare the development of the series. It can be hard to see which of the series shown is growing stronger or declining faster. Normalizing solves this issue by adjusting the scale and making it easier to compare the series.