Tall an' handsome

As of a couple of hours ago the Steam workshop has been giving problems - it manifests itself as showing a zero file size for assorted mods and subscribing won't do anything. A related problem is that you may not be able to remove the mod if you are already subscribed - other then manually removing it.

If you have a mod like that contact it's author and make him aware of the solution underneath:

Simply modify your upload to change the byte size and then push it to Steam again as an update