as i say to the person who alerted me to the term, i'm not sure i like this name for the phenomenon. it feels like someone used it to avoid legitimizing the phenomenon as an actual and not artificial perception.
it refers to the close proximity of observations of the same type of object, with a particular emphasis on newly acquired knowledge (e.g., you've never heard of michio kaku, but three people mention his name to you in the same day).
i'm not sure yet what i might call the narrower term, but i like phenotypical clustering for the broader. like just now, i went to make koolaid and the last packet was black cherry and then i went to the liquor cabinet to get something to bring to a dinner party tonight and grabbed a bottle of jim beam red stag bourbon which is infused with black cherry and in fact says "black cherry" in large font in two prominent places.
i think i'll bring some of this cherry coke zero in black cans with me as a mixer.
have a black cherry day.