I began writing a response to this post a long time ago, but the more I thought about the question the more involved my thoughts became. I had actually been thinking about this very question before the thread first appeared.
The responses here are amazingly varied and interesting. In my case, the influence of DS has meant finding correspondences between things on the show and events or places in my life.
After initially seeing DS at scattered times while in elementary school in the 1970s, it later dropped from my memory. Occasionally when some reference called the program to mind, I felt a sense of excitement combined with a sense of loss for something from the past that was gone forever. While attending graduate school in California in the mid-1980s, I happened upon several late-night broadcasts on a PBS station, which were sadly short lived. They were episodes from the Leviathan period, and I dimly recalled having seen some of that storyline as a child. This was the first time since childhood when I had really thought of Dark Shadows, but the influence quickly evaporated when PBS stopped showing it.
More recently, I was able to view the entire series thanks to the SciFi channel, and its importance in my life has increased. Viewing the series as an adult, I now saw correspondences from my childhood that I hadn't considered at the time I lived them. These were things such as a mansion we had visited during childhood, complete with an old adjoining cemetery, along a rugged, rocky lake shore, yet I don't recall ever thinking of that in terms of DS at the time. I don't remember it being at all spooky, but now looking back I think of this location as my version of Collinwood and Eagle Hill cemetery. My aunt lived in a Victorian era house nearby, but I didn't really appreciate the Victorian design or architecture at the time; yet now I look back and think of this memory in terms of the 1897 storyline. We had a grandfather clock at home, but it is only now as an adult that I see these things through a Dark Shadows lens. Collinwood was another world when I was growing up completely unlike the ordinary world I inhabited. So how can I look back now and find similarities between my life and Dark Shadows? I suppose it's a combination of escapism and a nostalgic imagination.
On my walks in the bigger city where I lived only a few years ago I was always finding houses that reminded me of those on the show, including one that I would describe as Jeffersonian that I always thought of as the Old House, another one that I imagined as Angelique's home during the Leviathan period, and a mansion that looked very much like Collinwood where I almost rented a room in the carriage house.
During the past year while living again in the town where I grew up, I've imagined similarities between the town and Collinsport. Touring some other old towns with another aunt, she told me about the old newspaper office she had visited and read many of the town's newspapers from the turn of the previous century. They even let her take many of the newspapers home to read, with a promise to return them! I immediately thought of the newspaper office in Collinsport where Barnabas and Julia sought information on more than one occasion. My aunt also talked about visiting a few years back with a man in his 90s at a bakery where he had worked since the early 1900s, and he claimed to recall my maternal grandfather's parents who were immigrants there in the 1890s. This reminded me of some of the elderly Collinsport residents such as the cemetery caretaker and the jeweler who had old records of dealings with the Collins family from earlier eras. One of the original jewelers in town here now no doubt has records going back a century, at least I would have that sense from my memory of the store as a childhood, and how ancient the store was even then. To step into the store is to walk into the past.
My interest in the past and in family history are something I share with Barnabas and other Collins family members. This was not an influence that came from watching Dark Shadows but something I was always fascinated with as far back as I remember, instilled by things I heard from family members, along with old daguerreotype and photo albums of ancestors. I was mesmerized by a tin type of my great-grandfather who died very young in 1897, the same year as a favorite DS storyline. Digging into the past of my ancestors has been one of my major occupations over the past few years, and I've come across people and events that have occasionally called to mind the Gothic genre in general. Some of the correspondences I can make with a movie that has touched a deep chord with me, "Eye of the Devil," seem almost uncanny (similarities with names, occupations, and locations). Not long ago I found a record in Latin of an old ancestor known as "M_______us Lupus." My heart almost stopped when I stumbled on that, because I seriously entertained the notion that this ancestor might have been thought to have been a werewolf; later I realized this was simply the Latin form of his surname, which was Wolf. Only a few years ago, when looking at the Collins family tree in one of the Pomegranate Press books, I was impressed with a family lineage known into the 1600s, which seemed the unfathomably distant past. Little did I realize that I would be able to research to that point, and earlier, in my own ancestry.
These are many of the parallels I draw now as an adult between my life and Dark Shadows; in making these parallels, I see how DS has influenced me.
