The reason for LJ being listed, BTW, is not that they themselves spam but that they provide hosting to spammers by not acting fast enough when it comes to deleting spam journals.
I think it's debatable whether this is actually justified. It seems that a bunch of spam journals listed by Spamhaus have indeed been up for weeks, if not months, without anything happening; and spam certainly depends not just on the ability to send email but also on the ability to host content, something that LJ is (unwittingly) providing here. And certainly, Spamhaus' mission of cracking down on spam and making it easier for network administrators to deal with it is a good and noble one.
On the other hand, Spamhaus is basically holding every genuine LJ user hostage, and they still do seem to relatively trigger-happy, all in all; Wikipedia mentions a case where Spamhaus apparently put the Austrian domain name registry (nic.at) on its list after the latter refused to delete certain domains that Spamhaus claimed were used for spam, citing legal concerns. Without knowing the details of the case, this does appear to amount to strong-arming someone into doing your bidding, and Spamhaus would be well-advised to remember that the ends do not always justify the means.
Whether the situation with LJ is comparable to that now is up for debate; I'd imagine there is a good chance that LJ is simply being tardy, neither a) deleting known spam journals nor b) implementing measures to keep them from propping up again and again. Perhaps the Spamhaus listing will serve as a wake-up call there, and at least Spamhaus does appear to have a reasonable process for getting of the list — quite unlike several other (past?) lists that had no easy way of contacting the people behind it, or took weeks to respond, or asked for payment (sorry, "donations") to remove listees from the list, or even all the above.
Nevertheless, the fact remains that LJ is being listed in a spam list not for spamming, not even for doing nothing about spam, but for not doing enough about spam, and that many, many legitimate users are being used as leverage to get LJ to do more about spam journals.
(Jef Poskanzer, who runs acme.com, has some strong words concerning blacklists, BTW, and John Gilmore is highly critical of them as well.)
Anyhow, this is the backgroud, so if you're having problems with comment notifications, either switch to an email provider that doesn't use Spamhaus (e.g. GMail), or use the recent comments page to keep track (a kludge, admittedly).