I am subscribed to the trac mailing list to follow reported bugs. When I get an email, the only useful information I can extract is the title of the ticket. For example,
If I click on the link, I end up in a non-render HTML page which is very difficult to parse visually. So, if I want to understand what is going on, I have to visit this website, find the relevant ticket, and find the new post. I think that the mailing list would be much more useful if it actually included the new comments, or if it provided a direct link to the post.