The date filter is based off of giving behavior in that date range. For example, if you select to see the last year, you will see information based off of all your fundraising over the last year.
Does this apply to my Giving Information and Constituent information? Yes! You can filter both. For example, you can go over to your Constituent Information Dashboard and select a giving amount between $50-$100 with a date range of the last year and you will see only demographic information for those Constituents.