Some early court rulings’ decisions applying new federal rules about accidentally disclosing privileged legal information are giving corporate legal departments new glimpses into best practice for electronic discovery.

Federal Rule of Evidence 502, which took effect in September 2008, aims to ease fears that companies could accidentally waive attorney-client or work-product protections when they turn over reams of electronic data during litigation. The rule imposes uniform federal standards regarding such waivers. The rule was also widely touted as a way to relieve the crushing costs associated with the discovery of electronically stored information, but so far it hasn’t seemed to live ...