Revenue is often cited as a barrier to physician-patient e-mail. This study suggests that patients may be willing to pay a small fee for this, generating revenue for the clinic:

This study suggests that patients of all ages are currently ready and willing to pay a small annual fee for online services with their primary care physician’s office. If 47.1% of a practice of 2500 patients each paid US $10 per year for online services, the annual revenue generated would be US $11775. Not only does this study support the economic feasibility of patient Web portals, but it suggests that online services could form a new line of revenue for primary care physicians.