As someone selling eBook as well as print versions of my novels, I’m grateful for any online article that discusses the new eReaders because these offer me a slightly more targeted opportunity to reach some of the people who might want to read my eBooks. If you’re marketing, however, it’s important to be clear about your purpose in leaving a comment. You’re purpose is to attract interest in your site and your work. To date, the marketing comments that seem to draw best for me tend to be sincere, authentic, relevant to the topic, thoughtful and, if at all possible, helpful somehow. A genuinely witty or funny comment can also work, but they’re a lot trickier to pull off. Expressing genuine enthusiasm for something can also draw positive attention. Bottom line: coattail marketing absolutely requires your best effort to reach and to serve others, so they’ll rightly assume that there’s more of the same to be had on your site and are tempted to visit.