SPSS Wiki is intended to be a reference and workbook for SPSS statistical procedures. It is for both novice and expert. While statistical procedures are explained to some extent, SPSS Wiki is not primarily a statistical text, there are plenty of other resources on the net for that.
This site goes beyond commercial printed workbooks in that more techniques are covered from data all the way to interpreting results. Despite all this, SPSS Wiki does not seek to promote SPSS or any other proprietary software. In fact, many pages include some level of criticism of SPSS. You can also expect that where alternative open source GUI packages are available they will be highlighted and encouraged.