Maybe easier to read on screen, but not easier to type or say to someone else. There was a previous comment about reading punctuation over the phone, which I've found true. In addition, there are lots of folks who are generally confused by which punctuation mark is which. My wife recently had a 5 minute conversation with someone who simply didn't know what a dash was (it's in her company's domain). As the SO brand spreads beyond the hacker community memorable word-based URLS without punctuation will be even more important.

My biggest problem with the series vs. individual sites thing is that I already have to remember so many URLs and information about my identity on each site. Where do I log in to see all of my notifications from the various sites? How do I find my friends when I move from one site to another? How do I see that a bunch of my friends are now answering questions on a cool topic on a totally new SE site? A series approach would have provided a much more straight forward approach to answering these questions. I think the unique sites make leveraging the asset of users who participate in many communities harder.