Hi FwF,
Good differentiation, and reflecting more the recent developments: malware authors deliver more and more on criminal demand, as valid credit card info is shipped for around $ 1.5, just to set an example. This also explains why the gigantic outbreaks of malware meant to infect as much computers as possible has not been seen lately. The main culprit is silent infectors for slime ware, and sellable botnets for a purpose, limited only for fire power.
My vision on this is it is more of a circular trend. First there is the webmaster with his or her specific demands, soon to follow is the adman, to be followed by the spyware creator, and to round it up there's the spammer. Virus artists are supportive of this or still doing it out of a feeling of a sort of geekiness.
The malware palette of to-day is the result of all this.
The answer to it can only be found in a multi-layered defense of all sorts of anti-malware programs (AV, AT, FW, SM).
And sometimes what rests is the 3FS = the three finger salute = Ctr + Alt + Delete,
polonus