We present different methods of data collection fi om the Web for informetr
ic purposes. For each method, some studies utilizing it are reviewed, and a
dvantages and shortcomings of each technique are discussed. The paper empha
sizes that data collection must be carried out with great care. Since the W
eb changes constantly, the findings of any study are valid only in the time
frame in which it was carried out, and are dependent on the quality of the
data collection tools, which are usually not under the control of the rese
archer. At the current time, the quality and the reliability of most of the
available search tools are not satisfactory, thus informetric analyses of
the Web mainly serve as demonstrations of the applicability of informetric
methods to this medium, and not as a means for obtaining definite conclusio
ns. A possible solution is for the scientific world to develop its own sear
ch and data collection tools.