The $UpdatedBy and $Revisions fields correlate
the time of a recent update with the user or server that made the update.
The position of an entry in the $UpdatedBy field is the user or server
who made a modification at the time indicated by the same position of the
entry in the $Revisions field.This information can be very useful in tracking
down the source of unexpected modifications, and it is used to help prevent
and save conflicts
each entry requires space within the database and additional overhead during
view updates and replication.
When setting a maximum, remember the correlation between the two fields;
it is of limited usefulness to have different maximums for the two fields.
We recommend setting both fields to a maximum of 10 entries, as this preserves
enough information to allow for troubleshooting questionable updates and
preventing conflicts but does not lead to significant overhead.