my friend, category rank are just to give an idea that if u have got reservation u got the better chances,just compare the gneral colum and category column,u will see that lower ranks are being getting into category as compared to the general....the importance of category rank comes during allotment process,at that time after each allotment remaining seat status will be given in the official site,suppose after first allotment if the obh seat in any branch is 2 and the waiting status of ur rank is 1 u stand a chance....hope u r getting what i am saying