We like to joke that putting "Docker" in the headline makes a great story. Welcome to our first great Docker story of 2015.

You weren't alone if you hadn't heard of Docker a year ago; the open source Linux containers debuted in 2013 and had their full-production release just six months ago. On the other end of the spectrum, though, are the Linux-enlightened who'll tell you that containers — a construct for treating an application and its dependencies, such as libraries, as a single entity — have been around forever. Docker just made them more practical and suited for being moved around a virtualized environment.

From there, the idea spread like a cat meme. Here's our recap of Docker's progress during the past year, and it can also serve as a beginner's guide to what's important in the technology coming into 2015.

1. The ABCs.
A good place to start is Scott Raynovich's "Dumbing Down Docker" column, an appropriately skeptical look at the Docker craze. Raynovich takes us through his own path of learning about the technology and why it's become such a hit.

2. The SDN Connection.
This stuff does have relevance to SDN, as we noted in our debut Docker story, which actually focused more on Google's Kubernetes tool for connecting Linux containers to a network. Docker does include some basic networking, but it's got a long way to go. Networking will be a big Docker story in 2015.

3. The Path to the Enterprise.
One use for Docker Inc.'s recent $40 million funding will be to spruce up the technology for enterprise use. The Docker Enterprise Hub, announced in October, will help feed that transition. Docker is trying to grow up quickly, and I wouldn't be surprised if Linux containers start feeling more "corporate" this year.

4. The Dandelion Effect.
Not to call them weeds, but Docker startups have been quick to emerge, with each seemingly encouraging others to sprout in its wake. A favorite example of ours is Socketplane, whose founders include OpenDaylight Project all-stars Madhu Venugopal and Brent Salisbury.

5. The Money Trail.
More fundings and acquisitions seem inevitable, following deals such as $5 million raised by the young Weaveworks (formerly Zettio) and $36 million raised by Mesosphere. Meanwhile, Docker Inc. continues to acquire startups, including those comprising of a couple of people working on one rather useful aspect — Koality and two-person Orchard come to mind.

6. The VMware Matter.
Linux containers could conceivably replace virtual machines. VMware doesn't fully dismiss this possibility, but instead of trying to wall off Docker with denial, the company is exploring ways for VMs and containers to become allies. It's all in the very early stages. Fargo, a container-plus-VMs project, was just getting started when it was unveiled at August's VMworld conference, and VMware's talks on the subject that week included lots of requests for input. Given Docker's fast evolution so far, there's a chance the questions here could start finding answers soon. VMware might not get its way, but the company is playing its hand correctly by trying to get in front of the Docker phenomenon.

7. The Rivalry. Like a plot twist setting up the sequel to a movie, a Docker alternative appeared late in the year. CoreOS closed out 2014 by launching its alternative Linux container format, one that purports to be more lightweight than Docker. People refer to it as Rocket, but that's the name of the runtime (the software that runs the containers); CoreOS' containers themselves are called App Containers. The project has just begun, so the emergence of these containers will be a story to watch in 2015.