1) In the olden days of Cognos ReportNet their Crosstab engine was very rigid.
2) Rigid in the sense it had its one particular way of wokring not that it has changed much but the way we can pass a context or even assosciate a context (otherwise dimensions of a crosstab) that govern the calculation of the metrics has evolved.
3)Initial implementations were had to be done in a specific manner Year,Month and Date had to be indented either Horizontally or Vertically to make sense for the measures to be governed by time and then year and month had to hacked hidden if they were not required on the report spec.
4)Drill throughs were a challenge as passing both the dimension parameters was a task at hand.
5) With the Cognos 8 and its releases Crosstab has improved day in and out.
6) Now if we need to drill through to a particular target report based on relational data it is not a task at hand anymore.
7)There is a Property (property) associated to the Dimensions of the crosstab which can be used very effectively to pass context of the dimensions to the target report.
8) There is a general misconception that a crosstab (atleast for the new comers) can only accomodate only one measure(is not true)
9) Infact now it lets us define a Default measure and then further lets us drop in multiple measure governed by the same set of Dimensions
10) Solve Order functionality has helped in implementations a lot
11) Any calculated field(%age calcs) can be achieved effortlessly using Solve Order
12) If a calculated field is dependent on other data items then giving it a Higher Solve Order tells the crosstab engine that the calculation has to be done only after the dependent data items have been aggregated or calculated hence generating accurate results.
13) There is a functionality to Overwrite Content of a particular cell location using an appropriate query calculation/data item.
14) The sorting has also greatly improved. Data->Advanced Sorting functioanlity gives Report Authors a huge amount of flexibility in the way they want their dimensions to be sorted.
15) Crosstabs can be put on top of a an already built cube (which actually is accessed as a Package recent 8.4 version) in the cognos connection enabling effortless drill up/down depending upon the cube's size and query performance.
Crosstabs can be used very effectively in time series reporting solutions since they are extremely dynamic in their span of dimensions posed by the report auther.
Moral of the story i have seen some amount of hesitation on part of report authors to use crosstabs (again this is completely my view) in the industry but with the evolving everyday scenarios crosstabs are very effective in portraying dimensional representation of data for canned reports.
