Check out Bronto's 3-part blog post series on optimizing your sign-up process:
Steve Atkins answers the question: Which is better UTF-8 or ISO-? over on the Word to the Wise blog.
Mark Brownlow talks about the interesting stuff you can learn by looking at your stats.
Looking for a job in deliverability or compliance? Check out the job posts on Al's blog
StreamSend has a nice overview of the CAN-SPAM requirements on their blog. Just keep in mind: complying with the law is just the bare minimum of what you need to do - so make sure you're compliant. However, complying with what ISPs ask you to do is what really matters.
Eric Farson discusses the new Spamhaus’ Domain Block List.