It took off like crazy for VPS hosting, until superceded (although I know of many that still use it). OpenVZ was popular enough to support the parent company

It took off like crazy for VPS hosting, until superceded (although I know of many that still use it). OpenVZ was popular enough to support the parent company Virtuozzo/Parallels/SWSoft (many name changes over the years) and the commercial Virtuozzo product is still sold: www.virtuozzo.com . The lack of OpenVZ being accepted into the kernel, is what eventually killed it IMHO. Since the cgroups and other code that underlies Docker/LXC etc. is in every kernel, it was only a matter of time until the default became accepted and then used widely.