You have control over your web presence, you can publish articles and speak directly to your visitors. The more you publish, the more content is indexed in search engines, the more searches you appear for. I recommend a blog for each web site that you can update quickly and easily.
For e-commerce solutions we use the Drupal and Ubercart system, however we do also work with Magento on request.
For monthly social media management, newsletters, mobile versions of your web site and other great services just check out the other links above!