All right, a question about how to handle 18 noob students logging in for the first time garnered a reply from
"@ Ignatius, you could use Second Life URLs, see If the person doesn't have Second Life, and have your students land where you wanted."
In other words community websites can post SLurls and new sign-ups using the SLurl will spawn in the SLurl location. I suppose I knew that, really, but somehow forgot. Therefore it's as I thought sounded best - that random noobs spawn anywhere they choose from the DG, but target population noobs like my hypothetical steampunk-lover signing up by way of a steampunky blog would spawn at the location specified in the blog.