If careering around the Web doing symptom searches is your bag, there’s still MayoClinic.com. Where WebMD is a corporation that started as an ad-supported health-alarmism site with revenues of $504 million in 2010, the Mayo Clinic is a nonprofit medical-practice-and-research group that started as a clinic. Mayo’s storied past as the country’s premier research hospital, in Rochester, Minn., and its storied present as one of Fortune's "100 Best Companies to Work For" surface in the integrity of the site itself, which—though not ad-free—is spare and neatly organized, with the measured, learned voice of the best doctors.