I'd have to echo Jeff's comments. When Wrox shut down I hunted around for lists to join to replace it. In the end I didn't stick with most of the new ones purely because you couldn't post via email. The convenience is a big factor. Even providing a link in the email in less than convenient. It means either another window in your desktop, or that you lose the page you were viewing and you have to wait for the page to load.

The only list which I did stick with was the sswug list, which works in the same way as the wrox list used to. I have yet to get a spam message through that list, although I don't how much work they have to put in at their end to cut the spam. I guess you could ask them how they do it.

Also although spam in increasing, there are tools to fight spam. The figures I've heard on bayesian filters are that they stop high 90s of spam with very few false positives.