Demandware offers high availability and scalable ecommerce solutions to major ecommerce brands like Adidas, Lacoste and converse to name but a few. Their model allows companies to deploy Ecommerce sites with no physical infrastructure set up time required.
They have a long list of 3rd party integrations of offer such as email marketing, campaign management, PSP, personalization, social commerce, tax applications, and ratings and reviews. All while running a multi storefront approach so business users can track performance across multiple locations.
With the takeover from Salesforce in my opinion it will allow them to really capture the customer journey at every omni channel touch point, online, instore, mobile / tablet and call center. Demandware already had a call center application which was pretty outdated, so the integration of salesforce for this element alone will be beneficial.
There will of course be all of the customer data which can be captured in Salesforce / Salesforce marketing cloud allowing companies to now offer a truly personalised experience, via customer segments, personalised push notifications, personalised offers etc all leveraging the power of salesforce.
I think the key competitive edge this will bring is the time to market, which is key for retailers. With both companies being cloud based and having a very strong background in cloud application deployments, they will now be able to offer a company the complete end to end Ecommerce / CRM / Marketing platform from day 1. With less headaches on the initial set up when compared to Hybris or IBM WCS.