Isn’t it an open secret that everybody uses proxies or OpenDNS to access Facebook in Vietnam? The government of Vietnam has blocked Facebook but a quick Google search will give you at least 10 different ways to feed your FB addiction (don’t deny it.. ha). Most people take the easy way and use one of the innumerable proxies. The techier of the lot harp on the advantages of Open DNS.
If you came here looking for a way to unblock facebook, look at this post instead