Web Bugs and RootKits
I had sent several emails to the abuse department of a large web anonymizing service that showed up in WHOIS when trying to track down the source of malicious ads that were serving up rootkits.
This company never responded to my multiple emails but I am sure they received my complaints because their automated service tried to send me a "Web Bug" like this:
"[REDACTED]_facebookhermes/images/web.p=
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Pro Tip: If you're gonna pretend you never received an abuse complaint you should disable your automated spyware