New 'Online Engagement Guidelines', published by the MoD yesterday, make clear that Forces and MoD personnel can make full use of websites such as Facebook and YouTube.
In a "liberalisation" of its social networking policy, the MoD said today that UK troops are no longer required to seek permission from their superiors to use Twitter or Facebook, but asks personnel to use common sense over the amount of detail revealed.
This is a change over earlier rules, under which personnel always needed to seek authorisation before publishing any work-related material.
An MoD spokesman said: "The MoD's new common sense guidance allows service personnel to talk about themselves and their work online, within limits and with advice to protect their security, reputation and privacy.
"We will be actively seeking their feedback on how the first edition of the guidelines can be improved.
"Think about what you are saying before you describe when you are going to Helmand with x, y, or z."
The MoD said it would actively sponsor soldiers who are willing to tweet or blog about life in the military, with tips for engaging an online audience.
The new guidelines are part of the MoD's ongoing digital engagement work, which recently saw an Armed Forces Day Facebook page attracting over 170,000 fans.
The 13-page MoD document follows news that The Marine Corp denied the ban was aimed at curbing its soldiers' freedom of communication.
In an unclassified memo, the Marine Corps said social networks are a "proven haven for malicious actors and content" with a high risk for information exposure. The ban is expected to last at least a year.