Can-Spam lays out some very basic guidelines designed to widen the gap between legitimate email marketers (like you) and the dredges of the junk-mail underbelly (not you). The law, which pre-empts the myriad state laws on the books (whew) and gives everyone four months to be compliant, does not apply to "relationship" emails (like account updates or invoices you send to paying customers or newsletters you send to paying subscribers) but squarely targets "commercial" emails -- basically any email designed to promote a product or service.
So here they are, the basics of Can-Spam:
The main thrust of Can-Spam is to prevent people from sending fraudulent, deceptive emails. So the law begins with the obvious: if you send a commercial email, make sure recipients know who sent it. Your "from" email address and name should be accurate and honest and allow people to email you back. (Note: with your design template, not only does your "from" information identify you, but so does the brand identity that frames your email's message.)
Again, this is designed to combat deceptive emails. Can-Spam prohibits the use of misleading subject lines in commercial emails and calls for advertisement emails to be clearly marked as such, though the law does not call for any specific method (like including "ADV" in the subject line). Crafting clear, concise (and honest) subject lines is something any serious communicator/marketer should be doing anyway.
This is aimed at junk mailers who grab email addresses off the web using a robotic script, or who create "dictionary attacks" to randomly generate addresses. Bad, bad, bad. (It also leaves anyone who is grabbing email addresses one by one -- without a script -- in a big gray area, so we strongly advise against that.) So long as you're sending to people with whom you have a business relationship (or who have actively requested your emails), you have nothing to worry about.
Your recipients need to be able to contact you in two ways: by emailing you back (using your from address) or by contacting you the old-fashioned way (using your physical address). Unlike junk mailers who are doing everything they can to hide, you're doing everything you can to be noticed, to encourage your subscribers to click, call, email or visit. Recently, we began hard-coding people's contact information into the footer of every template; if your template lacks that information and you'd like us to add it (free of charge), just let us know.
Can-Spam requires that you offer a clear and visible opt-out feature and (more importantly) that you honor all such requests within 10 days. Our TrueRemove™ feature makes sure every email you send contains that opt-out link and that any opt-out requests you receive are immediate and permanent. (We keep a permanent record of opt-out addresses in your account, just to make sure no one accidentally sends to that person ever again.)