This is content marketing 101. Links to and from krogers.com with relevant content are Google's number one and number two ranking signals. Anyone who doesn't understand this should consult with a professional.
There is always a best time and day of the week for sending to contacts you don't have enough data on. Typically, as soon as they sign up is the perfect starting point. For everyone else, collect data and adjust the time accordingly. This is the first thing you should be doing to get your feet wet with Big Data.
Most consumers and a large percentage of retailers don't understand what digital marketing is. Asking someone to judge effectiveness who has little understanding is pointless. Digital marketing starts with a website. In addition to web design/development, there are four distinct types of digital marketing. SEO, SEM, Email and Social.
A few bad reviews are better for online conversions than all positive reviews. Online consumers do not believe manufacturers' or retailers' claims. They do believe negative reviews. Information from manufacturers is still important to get the ball rolling and fill in the blanks, but money is made from reviews that are perceived as real.