Jeff Jarvis explains to Dell why their management/marketing response to customer complaints (not just him - they shut down their customer forums as well) is a really bad idea. Dell is running plays from a 1995 playbook. Sadly for them, it's 2005. Bad word of mouth doesn't just spread locally anymore - it crosses time zones in minutes.
I've said this before, and I'm sure I'll say it again: Define your message, or have it defined for you. Right now, Dell has been having their message defined for them due to a massive PR failure on the part of their management, marketing, and PR folks.
I've got 41 custom search feeds out there now, across multiple search engines and across multiple search terms that involve my company and our products. When a comment is made in the Blogosphere about any of that, I hear about it within minutes - and I respond via email or comments on the blog in question immediately, making it clear that a deeper conversation is possible if needed. Clearly, Dell doesn't realize just how crucial that sort of monitoring/response cycle is - and it's part of what's costing them money right now.