Well, I can also recall most things that way but without dates. I can usually remember what someone said, what they were wearing, what I or they were eating/drinking etc. It just doesn't work that way as with that person from this article. If someone told me "what did you do on 15th april 2006" I'd have no idea. I often have trouble with "what did you do yesterday".
But if they somehow described that day in short just so I could tell which one it was I could start describing everything in details.
My memory's pretty bad and very selective. I have a hard time remembering dates, movie titles, actors' names, etc. Basically, anything that would come up in trivia I am terrible at. I can see a movie five times and love it every time and still not be able to recall one specific line from it. It sucks when someone mentions a movie and I'm like "yeah, I've seen that one, I liked it" and they then mention a scene from it and I can't even remember.