Take two aspirin and tweet me in the morning: how Twitter, Facebook, and other social media are reshaping health care.

If you want a glimpse of what health care could look like a few years from now, consider "Hello Health," the Brooklyn-based primary care practice that is fast becoming an emblem of modern medicine. A paperless, concierge practice that eschews the limitations of insurance-based medicine, Hello Health is popular and successful, largely because of the powerful and cost-effective communication tools it employs: Web-based social media. Indeed, across the health care industry, from large hospital networks to patient support groups, new media tools like weblogs, instant messaging platforms, video chat, and social networks are reengineering the way doctors and patients interact.