Retrieving values from previous page

Hey Forumers,
Here is the case, I have a datalist displaying a whole list of text files and I have a hyperlink with the title as the text and a navigateUrl that navigates the user to a page to display the file the user chose.
I have coded the hyperlink like so:

<asp:HyperLink ID="HyperLink2" runat="server" Text='<%# Eval("Title") %>' NavigateUrl='<%# Eval("StoryID", "StoryDisplay.aspx?StoryID={0}") %>'>Hyperlink</asp:HyperLink>The problem I am facing is that I got this code snippet from another source and I don't know what does the StoryID={0} means. I do know that the eval statement would sent the storyID of the selected file to StoryDisplay.aspx, I just don't know how to retrieve the values from the second page.
P.S. the second page contains a ti ...