Spam, virus, phishing all fall under "abuse". Targeted advertising is the only new thing here.
It depends how ads are targetted. I personally think that even spam protection is very big privacy issue. Because things like Bayesian filters, collect extensive information about your messages. If I get your spam-filter rules, I know a lot about you, even if I don't get the actual messages. Actually spam filter info is perfect data for profiling, it's condenced form of your communication. Especially the words which indicate ham content. Which for sure will include any professional terms & project names you're working, primary contacts etc.