It worked okay for Shadow Unit because enough readers trust Emma and Bear and Sarah, so they were willing to take the time to learn who all these people are.
I think partly (at least for some of us) it also worked because we already knew some of the people in question through the LJs, and the snippets and teasers that had appeared on the site before 'Breathe' went live. It was actually rather better than promos for a new TV series, which seem to be mostly concerned with introducing you to genre and/or one big, important character/question as a 'hook'.
Not only did we have lots of hooks--so if one didn't grab us, another was likely to--but we had a map to the younger set of characters, and suddenly it was a case of, Oh, so
that's what Hafs/Daphne/Chaz looks like from outside, and these are all the people they've been talking about in code--okay, yeah, I know where I am...
At least, that's how it worked for me.
The LJ's didn't quite work for me, but the teasers totally sold me long before the first ep went live. I think we had glimpses of every character and enough of a glimpse that we got something of a feel for them so that we didn't go in completely cold.
And there is the trust issue.