11. A computer-implemented method for performing a data analysis task having an associated analysis context, the method comprising: defining the analysis context associated with the data analysis task, wherein data items have a variable relevance in accordance with the context, and wherein data items are grouped together to form logical transactions conducted by a user over a predetermined time period; receiving the logical transactions exchanged over a communication network; defining a plurality of logical transactions based on one or more transaction criteria, wherein each logical transaction of the plurality of logical transactions comprise at least two data items of the plurality of data items; processing the logical transactions with a set of prioritization rules to generate relevance scores that quantify a relevance of the logical transactions to the analysis context, wherein the relevance scores are assigned according to a common scale; and generating a prioritization of the logical transactions based on the relevance scores.
11. A computer-implemented method for performing a data analysis task having an associated analysis context, the method comprising: defining the analysis context associated with the data analysis task, wherein data items have a variable relevance in accordance with the context, and wherein data items are grouped together to form logical transactions conducted by a user over a predetermined time period; receiving the logical transactions exchanged over a communication network; defining a plurality of logical transactions based on one or more transaction criteria, wherein each logical transaction of the plurality of logical transactions comprise at least two data items of the plurality of data items; processing the logical transactions with a set of prioritization rules to generate relevance scores that quantify a relevance of the logical transactions to the analysis context, wherein the relevance scores are assigned according to a common scale; and generating a prioritization of the logical transactions based on the relevance scores. 13. The computer-implemented method of claim 11 wherein the one or more transaction criteria comprises a username, a time period, a packet address, an e-mail address, and a plurality of web pages linked together through a plurality of hyperlinks.