I think email marketing is much less effective than it used to be. Spam email has become to prevalent, and email users have found other ways to communicate. Nonetheless, it still helps to get the email address of users.
Make sure you let them opt-in. Don’t just go around buying email addresses and sending emails to people who did not agree to get them. Also, make sure you include a way for the recipients to unsubscribe. Taking those two steps will make sure your emails are not considered spam.
I find it better not to send out too many emails. I know personally that I start to ignore email lists that send me a bunch of emails with offers. However, if an email list sends me useful emails every now and then, I will pay more attention to them. If one of the emails includes an offer, I am more likely to consider the offer.
There are a few ways to turn your blogs RSS feed into an email subscription. I use that on my other two most major blogs. (I don’t use it on this one because webmasters almost always use RSS.) Collecting emails can be very helpful. You can use email newsletters to get old traffic back to your website. If you have a big enough email list, you can use it to market relevant products.
What do you think? Do you use email marketing?