Since our data center move last month, we've been tackling a number of different issues with regard to email. When we changed the IP address for livejournal.com we were put on a number of popular spam blacklists as a potential spammer. This caused not only email from us to be blocked, but also more stress on our mail systems trying to resend all the blocked email. When our mail servers become slower to respond, we queue mail in databases to be sent at a later date. Once these queues became too large, however, our system to retrieve the mail and send at a later date also became too slow.
We believe we've now found all the blockages for mail and over the next day you will be receiving the backlog of mail not delivered in the last couple of weeks. If you are still having any issues receiving email after the next day or so, please do open a support request.
Thank you for your patience and understanding.