Q. But I don't want an online journal--could I just use it to post to
the community one, instead?
Although you have to have a LJ journal /account/ to post to the
community, just because that's how LJ works, and that's how the
security settings are set up, that doesn't mean you have to use /your/
journal. Think of it as having a username--there's no need to actually
post to your journal.
Q. How can I control who views my entries?
You can set it so all your entries are viewable by only someone who
you've listed as a 'friend.' They will also have to be logged in. You
can set this as the default for all your entries, and even set
security levels individually, afterwards. See:
http://www.livejournal.com/support/faqbrowse.bml?faqid=120"
Q. How secure is it?
LJ is an open-source project, and only receives funding from its
members, meaning there are (to my knowledge as of writing this) no 3rd
party sponsors. You can download the source code and run it. It's also
built on PHP and MySQL.
Q. How much does it cost?
It's free, and doesn't require an activation code, even.
Q. Do I /have/ to?
Not at all! However, it's a great place for chatting, community, and
feedback. Check out the earlier post about the security hole, for
example. It's also a great place to post RP logs, to say hi,
and...ask for feedback about ideas.