Well, it's one of two things:

The most common version of the word is it's a technique used in older computers to copy a ROM into RAM. ROMs are typically quite slow, whereas RAM is a lot faster, so at power on a computer would copy the Video ROM into RAM, so it could be accessed more quickly. You'd often see a BIOS on a computer say 'memory shadowed' or similar as it went through the POST.

However, I know it more as a place I used to work, Shadowram Computers. We built custom PCs for home and office use. I started out there aged 15 after two weeks of work experience as a Saturday job. I'd build new computers, fix computers customers brought in, sell stuff, all sorts of things. I'd often work during the weeks over the summer holidays. It was a great job, and I learned (and earned!) a lot from it. We also used to build up a lot of second hand PCs - at the time you could still sell a 486 as a reasonably usable computer.

For me, it's a bit of a nostalgia thing. The company moved a year or so before I moved on and got a 'proper' job. It lasted a few more years and as I understand it eventually folded. That's why the domains became available. I've owned them for a few years, and always meant to do something useful with them.