bradfitz just posted in news that paid LJ users can enable auto-pings for their accounts. (The announcement is here.) Free users can still use the webpage interface if they're interested in having their journal listed there.
Why does this change matter? It matters because it means that LiveJournal is interested in being compatible with the major index of weblogs out there. It matters because it will help include LJs into the greater community of weblogs out there across all services. It's good both for publicity and for LJ playing nicely with everyone else. It's also a service that anyone used to many of the other big blog services would expect in a full-featured weblog/journal service, so it'll help the appeal of LJ to potential new users.
Note 1: None of this actually means there's any particular reason you would want to enable this feature. It's good for anyone interested in seeing how their weblog connects with other, especially non-LJ weblogs, across the next, and for anyone interested in self-publicity.
Note 2: I'm not sure LJ's implementation is working yet, despite the announcement. The only LJs listed on weblogs.com at the moment are so few and at such widely spaced hours that they must be manual entries. Honestly. When I first looked, the most recent LJ ping was 3 or so hours ago, and the service had been live for at least 45 minutes in theory.