Niall Mulrine, who lectures in schools on internet safety, says these pages often do more harm than good.
Mr Mulrine is from Ballybofey, the same Co Donegal town as tragic sisters Shannon, 15, and Erin Gallagher, 13, who both took their lives in recent weeks.
Such memorial Facebook pages attract huge attention from teenagers. A page dedicated to both sisters, set up just hours after Shannon’s death on Wednesday night, has now had some 30,000 likes.
Tribute pages set up in the wake of Erin’s death have had more than 18,000 likes.
However, Mr Mulrine warned: “We really need to sit down and to examine the damage these pages are doing.
“Children are often in a delicate state when they go onto these pages in the aftermath of a friend’s death.
“A lot of things are said in a high state of emotion and they cannot be taken back once they are out there for the world to see. Also it gives people a forum to vent their anger, which is not a good thing at such times.”
Research revealed yesterday shows social media use can lower some users’ sense of self-control over their lives.
“Using online social networks can have a positive effect on self-esteem and well-being,” said researchers Keith Wilcox of Columbia University and Andrew Stephen of the University of Pittsburgh.
“This momentary increase in self-esteem leads them to display less self-control after browsing a social network.”
In particular, researchers found social media users were more likely to binge eat and have a higher body-mass index. Frequent users also were more likely to have financial problems, including a lower credit score and higher levels of debt.