Comparisons have inevitably been made with the now-defunct Friends Reunited website.
That service produced an extraordinary quantity of reminiscence about British schools.
Facebook has now inherited much of that role through school and local-history groups.
It would probably be unfair to declare either source inherently more reliable.
Both depend upon self-reporting, and neither should be regarded as equivalent to contemporary official records.
Facebook does, however, sometimes provide an advantage.
In a well-established former-pupil group, members may recognise one another, identify photographs, correct dates and challenge inaccurate memories.
Where a group moderator also verifies membership, the likelihood of completely invented identities may be reduced.
It is not foolproof.
But historical research frequently depends upon weighing imperfect sources rather than discovering perfect ones.
