For scientists and scholars toiling at their research and publishing their findings, the most immediate reward from the scientific community is a citation, when fellow researchers read their work and include it among the footnotes of a newly published paper. This acknowledgement -- being "cited" -- indicates that a paper has been judged by peers to be significant and useful. Citations, however, can be hard to come by. Many papers are cited perhaps once or twice, and many others not at all.
At the opposite end of the spectrum are the blockbusters -- publications that have amassed tens of thousands of citations.