Email lists make life easier when it comes to getting the word out to your fans and sending press releases to the media. They're also cost effective. Web sites with outdated or stale information are death to self-promotion. Form Relationships Web sites are nice. Press releases are nice.
Email is nice.
That said, nothing is quite as effective as forming relationships and friendships with people in the industry. Attend as many cons as you can afford. Join a good writing group. Send thank you letters and holiday cards to the people who've been good to you. It has everything to do with treating people right.