To continue with the possible "spoilers," Beth Chavez was the name of the 1897 ethereal, blonde beauty who apparently, quite accidentally, fell off of Widow's Hill.
As far as others, who took that unfortunate slip (either intentionally or unintentionally) off of American soap opera's most famous promontory, I recall Phillip Todd inadvertently going over the edge after attacking the loathsome Jeb Hawkes, who, ironically enough, later went over the edge himself after Sky Rumson wrestled with him on the precipice, near the conclusion of the Leviathoan storyline. (Many Dark Shadows fans believe that Jeb's "trip" off of Widow's Hill was condign punishment, considering the fact that he had personally "offed" about half-a-dozen totally innocent people in Collinsport.)
Of course, Adam also jumped from the top, and was the only DS character to actually survive the impact. (Thank God that Dr. Lang had provided Adam with a head, apparently as "thick" as Sylvester Stallone's in all of those Rocky films!)
As to why Widow's Hill held such a macabe attraction to people, that is troubling. I do remember once seeing a bridge between, if I remember correctly, Massachusetts and Rhode Island. There was a sign placed next to the bridge, urging anyone who was despondent, not to act rashly, but to contact the local public health facility for help and counseling. It is an absolutely terrible thing, when a person becomes so depressed that he or she would consider taking their own life.
That scene in which Mrs. Stoddard is just about at the point where she is going to jump from the top of Widow's Hill is both a profoundly moving and disturbing one. I don't think that I was ever more relieved, then when Barnabas grabbed her from behind. (I guess after that, I always had a feeling of "uneasiness" whenever a DS episode focused on that truly eerie spot.)