Walmart is one of the largest retailers out there, but in terms of online shopping the chain could stand to play a fast game of catch-up. 

Lately, the company's been tweaking its digital strategy, going so far as to launch a 1,500-person wing called Walmart Global eCommerce. Right there, near Silicon Valley, it's experimenting left and right, much in the way other startups are doing. Walmart hosts occasional "hack days," writes All Things D, "working on whatever engineers want and then putting them into practice." 

But more importantly, it's refocusing its strategy on e-commerce and mobile, and has rolled out updates to its app that include shopping lists, budget tools and coupons. The idea behind the shopping lists, which can be created before you even set foot in the store, is that Walmart can avoid losing its customers to "the Targets, eBays or Amazons of the world," says All Things D, so long as it can keep them throughout the shopping process. Whether that will work over the long-term remains to be seen, but for now it seems like a good place to start.