updated 10:39 am EST, Mon February 25, 2013
Doesn't require Facebook account
Facebook has announced deals with number of cellphone carriers to temporarily offer cheap or free data for its Messenger apps. The partnerships cover 18 carriers in 14 countries, and may be a way of pushing Facebook in regions where it isn't the dominant social network. Some of the more prominent countries in the list include Brazil, Egypt, India, Ireland, Italy, the Philippines, Portugal, and Thailand.
The promotions should last three months or more, depending on the carrier. People notably don't even need a Facebook account, since Messenger can be used by anyone with a phone number. It does, however, become easier for contacts to find each other when they have an account. Several versions of Messenger are available; aside from native iOS and Android apps, people can also use m.facebook.com or Facebook for Every Phone.