 <body>    <!-- wrapper -->    <div id=wrapper>    <!-- title -->   <div id=title><img src=title.png alt= /></div>   <!-- form wrapper -->   <div id=form_wrapper>    <!-- form -->    <form action=thankyou.php method=POST>     <!-- ... ... -->    </form>    <!-- /form -->   </div>   <!-- /form wrapper -->  </div>  <!-- /wrapper --> </body>I can almost understand the <!-- /wrapper --> at the end, because it's so far from the start of the tag/pair...  but seriously, what's the point of the opening comment lines?  I wouldn't ask the question if I didn't see this all the time.  I feel as if I'm missing something.  Maybe there's some unwritten best-practice involved, though I fail to comprehend what it could possibly be.  More than likely it's just obsessive-compulsive behavior.How do you guys normally comment your markup, if at all?
Why do so many developers do this in their HTML? 
comments;html
Some times CSS class names are generic and aren't specifically named. For example, what if you had<!--Code before--><!--Column one--><div class=center-bold>    <!--Tons of lines--></div><!--End column-->Wouldn't it be nice to know what your starting? I surely wouldn't want to scroll all the way to the end to find out that the whole div was a column. 