Online wealth management services offer a lower-cost, automated approach to personal investing that's challenging and transforming the existing financial advisory paradigm.

In fact, this shift is so seismic that four leaders among these "robo-advisors" have placed in this year's third annual CNBC Disruptor 50 list of companies shaking up their space: Personal Capital (No. 14) Motif (No. 23), Wealthfront (No. 34) and Betterment (No. 36).

Paladin Research & Registry has compiled a list of five ways these new, so-called robo-advisors differ from traditional brick-and-mortar financial advisory firms staffed by ... humans.

Robo-advisor definition: An online service provider that provides automated investment management with limited human contact.

Financial advisor definition: Located on Main Street in your city. Provides personal advice and services with an emphasis on human contact.

By CNBC's Kenneth Kiesnoski
Updated 15 May 2015; originally posted 21 April 2015

Robo: You complete a questionnaire that assigns you to a portfolio model.

Financial advisor: Personal advice can be tailored to your particular situation.

Source: Paladin Research & Registry

Robo: Limited human contact using telephone, email, Skype.

Financial advisor: Unlimited human contact that can be face-to-face, telephone, email, Skype.

Source: Paladin Research & Registry

Robo: May be limited to investment services.

Financial advisor: Can provide planning, investment, and insurance advice and services.

Source: Paladin Research & Registry

Robo: Limited to passive investment processes and passive management to further minimize investment expenses.

Financial advisor: Can provide passive management, active management or a blend of the two—selected by client.

Source: Paladin Research & Registry

Robo: Automation and low human contact enable robos to provide low-cost advisory services.

Financial advisor: More expensive than robos due to increased human contact and personalized services.

Source: Paladin Research & Registry