using countifs to track unique values over a date range

[msnyderxc]

Hello!

I am trying to track users and the number of times they use a product over a (-90/90) time frame of a date the product is presented to them. Basically tracking the effectiveness of the presentation. I have already tracked product usage, but want to track when unique users adopt this product as well. I have a great start on the spreadsheet attached, but need this one last formula.
Help????

[dnchari]

Did you get the answer? Otherwise I can suggest solving this using R, but not excel.