8. A method according to claim 2 wherein said using includes using said at least one output to perform a single second computerized text-classifier based document categorization process using a single text classifier, on the N+M electronic documents including the N documents and M additional documents.
2. An electronic document analysis method using a processor for analyzing N electronic documents, the method comprising: performing at least a portion of a first computerized text-classifier based document categorization process on the N electronic documents, using a first computerized text-classifier, thereby to generate at least one output; and using said at least one output to perform at least a second computerized text-classifier based document categorization process on at least M additional electronic documents, wherein said using comprises applying the first computerized text-classifier based document categorization process to at least the M additional electronic documents, only if the processor has determined that the first computerized text-classifier, when applied to at least the M additional electronic documents, satisfies a predetermined categorization quality criterion, and otherwise, applying a document categorization process which is not based on the first computerized text-classifier based document categorization process, to at least the M additional electronic documents, wherein a single set, X, of control documents is used: both to make a first determination of whether or not the first computerized text-classifier, when applied to at least the M additional electronic documents, satisfies a predetermined categorization quality criterion, and also to make a second determination of whether or not said document categorization process which is applied to said M additional electronic documents and which is not based on the first computerized text-classifier based document, satisfies a predetermined categorization quality criterion, thereby to utilize a single categorization process applied to said single set X rather than conducting separate, first and second, categorization processes on separate, first and second, control sets to be used when making said first and second determinations respectively.