This is related to, but not the same as my previous post. Again, this is mostly in relation to multiuser installations.
The naming of the directory structure for file-based caching concerns me. I haven't tested this out to see how it works, but I'll just put my concern out for the developers.
W3 Total Cache gives each site in a multiuser installation its own cache directory that contains the domain name of the site. So, if I have a site with the domain name someblog1.com on a multiuser installation, I'll get the following directory:
What concerns me here is the reliance on the domain name. That can change over time - a company buys a new domain name, decides to move the site to a subdomain, or whatever. If W3 Total Cache relies programmatically on the domain name staying the same as the caching folder name, that's not an optimal solution.
Better would be to rely on the blog ID, which will not change, even if the site's domain name changes. If W3 Total Cache relies on the changeable domain name and cache directory name matching up, I'd like to request that this be changed to matching the immutable blog id.