Where did you find it/this?
Your friend is more likely to say "Have you seen...?" than "Did you see...?" (Or "When did you last see...?" or "When was the last time you saw...?")
I have not seen him SINCE October.
I did not get to see my brother when I had a business trip to Toronto.
I didn't bring in the trash cans when I got home and now they are blowing down the street in this wind.
Use it when you echo a question that asked "Did..."
Did you see Grimm last night?
No, I didn't.
Use "have not" when you are talking about something that started in the past and continues to the present.
I haven't seen the new episode of Grimm yet, but I recorded it and will watch it tonight.
I haven't eaten at the new restuarant yet, but it looks good.
Use it to echo a question asked in the present perfect.
Have you ever used Yammer?
No, I haven't.
Student or Learner