Considering that my childhood horror was more along the lines of Scary Stories to Tell in the Dark, Shivers has nothing on the kind of chilling tales I grew up with.
While I can see some younger readers being disturbed by the eerie (read:ghostly) communication, the plot itself leaves much to be desired with little explanation given for the events, or culpability of the characters up until the last chapter. In addition, the nature of the plot elements has dated this book significantly, such that newer readers will have difficulty connecting to it.
Regardless, I would be interested in seeing what the rest of Shivers has to offer, if for nothing else, to see what late 90s early 2000s kids were exposed to in the 'horror' genre.