Gianluca Fiorelli asked on Twitter why does Google sometimes show the source of their answers in the knowledge graph or quick answers and then sometimes does not?

I asked Google this question and I got a response, which I posted at Search Engine Land this morning.

The response:

(1) Example of basic factual information without a source link:

(2) Example of not widely-known information with a source link:

(3) Example of not widely-known information without a source link:

Of course, many SEOs are not happy with the swiss army knife answer from Google’s Amit Singhal and they may not be happy when they hear this.

Forum discussion at Twitter.