While it seems kind of ironic for me to be helping Blogger, I'm glad to do it under the circumstances. There are just too many advantages to getting syndication working well for everyone... plus, a working boing-boing feed is a nice thing for LJ users to have access to.
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update - Cory from boingboing says that he thinks Blogger hasn't fixed the problem yet after all, and that what happened is that the offending characters scrolled off his RSS feed instead. However, the team at b2 is taking steps to avoid this problem in the future until such point as Blogger fixes the bug.