No one liked IBM but I wanted OS/2 to succeed anyway.
There is no 'best' way to spamfilter bad emails. The definition of spam is unknown and being redefined constantly by spamfilters (which is a little different from what recipients think spam is).
The problem is that the process of 'what is spam' is quite complex for humans. For instance: Suppose I gave you permission to send me bulkmail and you only start to use it two years later. Is that spam? For one person it isn't, for the other it is.
Consultants are mystical people who ask a company for a number and then give it back to them.