I'm wondering if
<embed> tags get used to crawl and/or affect SEO rankings.
Say I'm making a "widget" of HTML (maybe eventually a Polymer web widget) but let's say it's just a plain old HTML5 embed:
<embed src="http://www.example.com/some-widget/" style="width:500px; height: 300px;">
Also, assume my widget URL returns HTML containing a set of images. Would these image URLs get crawled as if they are part of the parent HTML document?
I guess my question could be rephrased as, do crawlers index tags during the crawl? Would Facebook's URL preview generator perhaps behave the same way (e.g., the thumbnail image)?