The botnet population is huge. According to a study by McAfee, "at least 12 million computers around the world (are) compromised by botnets." That means the botnet operators are controlling a population roughly the size of Guatemala. In fact, the number of infected systems would place it at about 70 out of 230 sovereign states and territories. More than Greece, bigger than Hungary, Belgium, Portugal or Cuba, and just a million behind Zimbabwe and Ecuador. The Czech Republic, Bolivia, Sweden, and the Dominican Republic would all be smaller.
While broadband users are favorite targets, dial-up users are equally vulnerable. Various studies have demonstrated that an unpatched, unprotected system can be compromised in as little as 5 minutes online. And if you're thinking it can't happen to you, think again.