Facebook already knows what users "like" and have attempted to decifer what kind of mood a user is in, and now, according to a report, Facebook may soon know the state of a user's health.

"Support communities" may be available to Facebook users suffering from various ailments. The social media behemoth is setting up a research and development unit to test new health apps.

Some of the headwinds the company may face are privacy and advertising issues.

A user looking for support from a community forum with similar health concerns might not want other users or their friends knowing why they joined a particular community.

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"Facebook is going to have to look at all those kinds of issues. I'm sure they're aware of it but they're also aware they have to make some money off of the site," said Jill Duffy, writer for PC Mag.com.

"Gathering big data for health and medicine is actually really great and valuable but it needs to be done right and with careful consideration," she said.

"On one hand, we're looking at how are advertisers are going to be using this data if they're able to see and the other angle is are other users on the site going to be able to see it," Duffy said.

Offering health care can engage more users on the website.

"I think it could be a big win for Facebook, especially for the people who aren't really savvy about using the web in general," Duffy said.