On Copyblogger recently we've talked about why it's so important to make your website mobile-friendly . And we've hammered on how critical it is to get people onto your email list . But there's a problem: it can be really hard for your mobile visitors to sign up for your newsletter. Here's why: Most mobile-friendly themes )in WordPress or other content management systems( hide the sidebars. They show just the main content area. For example,