"I'm making a reference to, for example, an announcement of a marriage or death in an on-line newspaper, which will give the user some background."
Those are items about which I would normally consider citing either with an existing event or creating a custom event (e.g. engagement announcement or a media profile of the deceased beyond the normal brief obituary, sometimes published well after the related event).
But your idea still has merit. For example, I recently discovered, by census, that an ancestor had been a resident of the "New York City Poor Farm". I'd never heard of that before and proceeded to create a story in order to enhance the profile entry. It would have been considerably easier (and arguably more appropriate) to facilitate presentation of the website source had your suggested feature been available.