Here’s the basic idea of a letter I sent to Marco at support@tumblr.com - I thought it would be worth posting here as well for community feedback.

It would be cool if you could add an extra class to post containers, so you can style them differently based on what content they hold.  Here’s what I mean:

Currently this wrapper holds everything

<div class="container"> BORING

Instead, do this:

<div class="container twitter"> 
<div class="container text">

<div class="container photo">
<div class="container quote">

<div class="container link">
<div class="container chat">

<div class="container audio">
<div class="container video">

<div class="container delicious">

Now we can style content based on it’s context.

What do you think?  Do you think this would be a good approach?  I think this would be the launchpad for some really creative tumblr designs.