The NASA Astrophysics Data System (ADS), along with astronomy's journals and
data centers (a collaboration dubbed URANIA), has developed a distributed
on-line digital library which has become the dominant means by which
astronomers search, access and read their technical literature. Digital
libraries such as the NASA Astrophysics Data System permit the easy
accumulation of a new type of bibliometric measure, the number of electronic
accesses (``reads'') of individual articles. We explore various aspects of this
new measure.