Every man who loves voluptuous curvy women should thank Roberta Smallwood for any plumper picture or movie they've jerked off to. Before Roberta there was almost no bbw porn - certainly nothing mainstream, you might be able to buy a grainy, black and white mag at a local sex shop if you were lucky. Roberta sparked mainstream interest in big women with huge tits and reached cult status by the end of her short and sweet career.
I don't know why Roberta turned to modeling. I do know she was a hairdresser living in Phoenix, Arizona (where most of her pictorials were shot). Her last movie was in 1993 (I believe) then she disappeared back into her life.