We ought to start actually sending some content with expiry headers on to reduce a lot of the work out backend servers are doing.

Currently, very little seems to actually be getting cached, defeating the point of having a Varnish layer. Caching more common objects like CSS/JS, frequently requested images and high traffic pages will give the backend servers more resources to play with the ability to start dedicating some of that "recovered" server time being available for use on other types of content (such as video renders/processing for TMH), generally handling more traffic and running jobs more frequently.

It will also improve load times slightly for most users who visit more than one page!