Writers of academic Computer Science publications generally follow the same conventions as other scholars, by citing previous work on the same subject. Citations typically are either to provide definitions and background information (typically a representative textbook or survey paper), or to give credit for previous work upon which the current paper is based. One exception is textbooks, where some of the authors have dispensed with the practice of citing sources.
As a measure of achievement and research quality, the practice of counting citations is not as prevalent in Computer Science as it appears to be in some other disciplines. One likely reason for this is that the published citation indices have never managed to keep up very well with the proliferation of CS publications, and in any case do not cover technical reports and conference proceedings. CS research papers probably achieve their greatest readership through these early publications, which are followed carefully by competitors in the same research area.