An account's home screen used to be one fixed layout. Now you build it yourself.
At the top there is a bar of tabs, and each tab holds a grid where you drag widgets around and resize them. Per widget you pick from the library what it measures, which period it looks at, and what shape it takes: line chart, bar chart, pie chart, table, a single number, or a list of the records themselves.
A widget that shows records can also carry its own filter, using the same filter language as the list screens. So "open tasks this week" sits next to "new contacts per day" on the same tab.
The counting happens in the database rather than in the screen, so a total stays correct even with tens of thousands of rows underneath it.