It depends on what age range you are looking at. More of the older generation will remember Fred Flintstone and hardly even know about Rihanna, whereas the more modern generation will know about Rihanna and will never have heard of Fred Flintstone.
Fred and Welma Flintstone gave birth to Pebbles Flintstone, whom is best friend with the boy next door, Bam Bam. Did you know that Pebbles and Bam Bam were eventually married, making Fred and Welma Flintstone the in-laws of Barney and Betty Rubble? ~Apple Juice