Only enterprise-level users can recommend items. You can tell if you are an enterprise user by whether an organization name appears in the top navigation bar. If you see an organization name, you should also see a Recommend icon on the bottom of content tiles.
You can click the Recommend icon on the bottom of the content tile or use the Recommend option from the More Actions menu to recommend an item.
To recommend an item to more than one user or group, enter all the group names or usernames in the Search by Name or Group field at once. You must include the same message with all recommendations you send at one time. If you cannot recommend an item to a group, you may not have permission to recommend to that group. You can recommend items to any member of your organization, whether or not you follow them or they follow you, if you have the recommendation permission.