I'm not the first person to point out the fact that the events of I Still Know What You Did Last Summer actually take place two summers after "What You Did", making this sequel's title a misnomer.
So, what should it have been called?
I Know What You Did Two Summers Ago?
Watch Us Crap On The Memory Of What Kevin Williamson Did Last Summer?
I Now Know That You Knew Last Summer That I Then Knew What You Did The Summer Before That?