DevOps is a rather overloaded term at the moment. I've seen it refer to any of the following:
- Encouraging collaboration between your Dev, Ops, and QA teams, with some cross-training so they can work together better
- Merging those teams under the same manager to try to improve that collaboration
- Making your developers responsible for all those roles, and never hiring a dedicated sysadmin or QA engineer
I personally think any of those is fine. Startups will err toward having fewer people and all of them be developers, while in a larger company it probably makes sense to specialize more and make "DevOps" mean close collaboration between those teams.
Of course, I've also seen "DevOps" as a job title for what would have previously been a "system administrator" or "site reliability engineer", and I have much less patience for that. :) Occasionally I see a job posting for a role that is actually dev + ops, but most often a "DevOps" posting means "we need a sysadmin, but we don't think sysadmins are cool enough to work here."