Innovation is the key to success in online retailing, which is why Internet Retailer magazine highlights each December the Hot 100 retailers and Top 10 mobile merchants who stand out for the new ideas they’ve introduced in the past year.

The editors of Internet Retailer look for original marketing concepts, smart new navigation methods, site designs that instantly engage the visitor and groundbreaking adaptations to new online trends. For example, Buy.com’s home page  shows visitors who are signed in to Facebook what their social network friends have bought or applauded on the e-retail site, or what other consumers are viewing at the moment.

This issue highlights the smart thinking of e-retailers of all sizes, old and new, and of every description—web-only, retail chains, consumer goods manufacturers and catalogers. The one thing they have in common is that each of these e-commerce sites offers lessons that other web retailers can learn from.

Examples from the 2012 Hot 100 list include furniture retailer Room and Board, whose site helps a consumer determine whether a particular sofa or easy chair will fit through her doorway and how; FreshPair.com offers a free consultation with a bra expert and sends shoppers samples to try on at home; and Netflix has come up with a cool way to let kids navigate its site, using images of cartoon characters to guide young viewers to their favorite shows.

The Mobile Top 10 list highlights retailers whose mobile commerce sites and apps make shopping easy and enjoyable on smartphones and tablet computers. Among the coolest iPad apps is one from Sephora that lets a consumer watch a video of an expert applying makeup while simultaneously watching herself try to follow the expert’s lead. SwimOutlet.com knows mobile shoppers may be seeking help while in bustling stores, and offers mobile live chat. The shopper can hide the chat browser window to visit another site; an alert bar on the SwimOutlet.com site flashes when a chat agent is ready. There are times when a text chat is the best way to get help, says Alexander Sienkiewicz, chief marketing officer. “In a noisy environment,” he says, “the phone may not be the best way to reach customer service.”

That’s the kind of smart thinking that characterizes the retailers in the Hot 100 and Mobile Top 10. For a full list of the Hot 100 and Mobile Top 10 click here.

This special issue of Internet Retailer can be ordered here.