Update - fixed:

Apparently the plugin was working all the time; I just deleted all my entries and made a brand new one and THIS time it seemed to work. This is the code I set up in my View template:

<div id="article-detail" class="grid_12">

{exp:weblog:entries weblog="news_articles" limit="1" status="Open | Top Story | Featured Top Story"}
<h2 class="article-title">{title}</h2>
<h3 class="article-author"><span>By</span> {author}</h3>

{article-body}

{exp:videoplayer src="{video-content}" width="400" height="400"}

{/exp:weblog:entries}

</div>

It outputs this page and now the video shows up inline at the bottom of the page: http://nerkin.com/news_articles/view/a_piece_of_george_orwell/

So if the plugin doesn’t work right away, try to make a brand new blog post once your settings are correct and see if it works after that. In my case - it did! PS: I have not tried this with anything other than a YouTube video.