I didn't get the concept and bookmarked every post I read in the first few hours. After using the board, I realized this was unnecessary.
I went to "My Chow" and clicked on the delete link next to each bookmarked post and they went away. However, next time I clicked on "My Chow" all the deleted posts were back.
Tried signing on and off. Every bookmarked post still appears on my page. Hope reporting this here is ok.