Wait, what?

Right, I've seen it done that way. However, I wanted to be able to access the articles as separate files without first pre-processing the archive to create a block index and writing a custom FUSE adapter to extract the files on demand. SquashFS is similar to an indexed archive, except that (a) it's more structured; (b) it's a more general solution, and (c) you don't need special software to read the filesystem image, as SquashFS is available by default in recent Linux kernels (with backports available for older ones).