In an SSRS 2008, I found that I can use the following value 'right(User!UserID,10)' as a parameter value to obtain the userid of the person running the ssrs 2008 report. However I would like to know where this userid comes from? is this from windows authentication?
Also I would like to know if there are other ways to obtain the userid for the person running the report? Would you tell me and/or point me to link(s) that will tell me how to obtain the userid from other methods?