LinkedIn groups have the option to enable a Jobs section and associated discussion area. Potential employers can post jobs directly to the group site – if they know the group is there and if they feel like investing the time. Think about how many different groups might be out there for different skill sets and you see that something that seems like an obvious move doesn’t seem so obvious to the person trying to fill a lot of different vacancies.
A partial (or better, we’ll see) fix is to set up a job feed that pulls in matching jobs from LinkedIn. I’ve just set one up for Orlando, you can take a look here. Feed might have you thinking RSS, but as far as I can tell there isn’t one – you have to browse the site or wait for your daily/weekly group digest email. We’re going to let it run for a few weeks to see if it useful or just noise.