eBay expanding its portfolio once again, but this time the purchase is about satisfying instant gratification in a way other than mobile commerce.

The online auction house has bought Shutl, a London-based private company with same-day (and sometimes same-hour) delivery resources in Manhattan and Chicago.

Promising a more personalized experience than other delivery services, the Shutl system is set up to route each delivery to the best possible carrier based on the following metrics presented in real-time: product price, performance history, quality ratings, and customer feedback.

Shutl founder and CEO Tom Allason explained further in a blog post on Tuesday about the premise behind his company, remarking, "E-commerce is quick and convenient, two things that delivery is not."

With eBay now providing both more manpower and financial resources, Shutl will be lined up with the existing eBay Now coverage, which will be expanded to 25 markets by the end of 2014. eBay also plans to make use of Shutl's existing same-day delivery scheme in Chicago starting today.

Financial terms of the deal have not been disclosed.

The acquisition of Shutl also points to another e-commerce trend not limited to eBay: Online retail giants continue to struggle with what could be the one thing holding them behind brick-and-mortar stores: instant service.

Certainly, the likes of eBay and Amazon have the capability to offer bargain basement prices on brand new products -- and even have them ready and shipped overnight. But there still isn't quite a replacement for being able to walk into a store and make a purchase immediately and spontaneously.

Amazon has been dabbling with its own same-day delivery services around its home base of Seattle for some time now, while Google has been testing its Shopping Express service around the Bay Area.

Devin Wenig, president of eBay Marketplaces, touched upon the topic in Tuesday's announcement, acknowledging that "the world is changing, with the lines between online and offline commerce blurring and the expectations of buyers and sellers rising rapidly."