Below is a screenshot of Google search using keyword Google recommend iframe seo:
And according to https://www.deanlong.io/
According to Google Search Central (straight from the horse’s mouth from the folks at Google), the use of iFrame content is not at all recommended.
In fact, Google says – in no uncertain terms – that “We recommend that you avoid the use of iFrame’s to display content”.
If you enter the page, you will find the citation is listed:
- The citation contents displayed by our Smart Embed Code widget are indexed by Google.