Tom Critchlow believes those annoying email chains can help build links. "I used to hate those people," he wrote. "I really did." But at the core of SEO, it's all about link-building. So, Critchlow discusses how to get links from linkbait, offering up a list of tips and tricks, including information on email chains to build links. Don't stop at Digg, Mixx, Reddit or StumbleUpon when trying to attract links, but rather go after the more than 120 social bookmarking sites and several dozen niche sites Critchlow mentions in the post because you don't always find your audience …