While it may seem outdated it's not necessarily a bad design. You can use PHP or Perl (due to it's string parsing capabilities) and simply store the main page on the disk.
Here's your sudo code/design...
You'll need need an html page that looks as follows
<tr><td>email</td><td>comment 1</td></tr>
<tr><td>email 2</td><td>comment 2</td></tr>
<tr><td>email 3</td><td>comment 3</td></tr>
Then you'll need a php script page that will read this html file in and display it.
The php page will also contain code for dealing with a user submitted comment. When a user posts a comment you need to open the html page with the rows in it and append to that file.
You need to be careful with this design however because you may run into write concurrency issues if two people attempt to read the file at the same time. Add code to handle this gracefully accordingly.