Over the years, I have heard or read many comments from genealogists about who owns information posted to the World Wide Web. In fact, many people are reluctant to post their family trees online because "someone might steal the information." A short article published in the Gizmodo.com web site uses non-lawyer English to explain several of the issues concerning legal "ownership" of information posted online.
If you have concerns about ownership of online information, you might want to read Who Actually Owns Your Content When You Post It to the Web by David Nield at http://bit.ly/2ypjoQU. The article is a few years old but still seems to be 100% accurate.
I will offer one thought to keep in mind: names of people, along with dates and places of birth, marriage, death, military service, and similar facts of interest to genealogists are just that: facts. As stated in the article by David Nield, "You can’t copyright facts, or ideas, or systems..." While you might be in possession of certain facts about your ancestors, that doesn't mean that you OWN the information. No one person "owns" facts within the U.S., according to copyright law.