From: http://en2.wikipedia.org/wiki/Traditional_Catholicism
Traditional Catholic is a term used to describe those individuals who, despite claiming to be Roman Catholics, reject (for instance as modernistic) some or all of the reforms instituted after the Second Vatican Council, especially the Novus Ordo Missae, that is the revised rite of Mass. They are to be distinguished from so-called conservative Catholics who may merely prefer the older Tridentine Mass, codified as the "Mass for all Times" by Pope Pius V's Quo Primum which stated, "We grant and concede in perpetuity that, for the chanting or reading of the Mass in any church whatsoever, this Missal is hereafter to be followed absolutely, without any scruple of conscience or fear of incurring any penalty, judgment, or censure, and may freely and lawfully be used."
What differentiates "conservative Catholics" from "traditional Catholics" are their attitudes towards and responses to the documents (and interpretations thereof) of the Second Vatican Council and the postconciliar reform of the Order of the Mass contained in a new edition of the Roman Missal - the product of a Consilium set up by Pope Paul VI. The former give their assent to all the post-Vatican II reforms while seeking a more "conservative" interpretation of them; the latter maintain that many or all of the reforms are wrongheaded and must be rejected. There is therefore a certain inadequacy to these labels. Today's "conservatives" are in fact entirely different to those conservatives in authority in the Church immediately before, during and after the Second Vatican Council - ironically they are more akin to the liberals of that time. "Traditionalists," on the other hand, mirror the old conservatives almost exactly. Because of this discrepancy it is becoming more and more popular today to refer to the former not as "conservatives" but as "neo-conservatives" or even "neo-Catholics." The prefix "neo" is used because these people are not the same as the conservatives of yesteryear, indeed it could be said that they are not the same as Catholics of yesteryear. This odd situation is well illustrated by the case of Joseph Cardinal Ratzinger. Cardinal Ratzinger is today labelled "ultra-conservative," but in actual fact the Cardinal was a radical leftist theologian during the Second Vatican Council and he has admitted himself that he has not moved to the right in four decades, but that the Church and the world has moved so far to the left that even a progressive of his conviction now looks conservative.
Traditional Catholics can be generally divided into two groups. The majority of traditional Catholics, while opposing some recent Vatican decisions that they see as contradicting former teaching, still claim union with Pope and accept his authority. The smaller, second group, called "sedevacantists," believe in the papacy itself but reject one or more of the "Vatican II popes" (Pope John XXIII, Pope Paul VI Pope John Paul I, and Pope John Paul II) as antipopes owing to their belief that these men are heretics due to many of the Vatican II decrees and subsequent papal promulgations. Some of these sedevacantist groups have elected popes of their own.
Traditional Catholics see the Second Vatican Council as a Council
whose documents were marked by an ambiguity which has led to
error or indeed contained errors themselves. Foremost among these
perceived errors are:
a new collegiality which they claim has weakened the papacy and
made Bishops' conferences a veritable "second earthly head" of
the Church. Traditional Catholics see this as contradicting Pope
Leo XIII's Satis Cognitum the documents of Vatican I, and other documents
and teachings. Ironically, in spite of traditional Catholics' firm
support for the papacy, they often accuse mainstream "conservative
Catholics" of an attitude bordering on papolatry (pope worship)
rooted in what they see as the latter's limited understanding of
papal infallibility and the nature of Christian obedience. They see "conservative
Catholics'" as misunderstanding the documents of Vatican I
and the scholastic understanding of true obedience as characterized
by Thomas Aquinas in his Summa Theologica, II-II-104.
Society of St Pius X (http://www.sspx.org/)a
priestly society, founded by the late Archbishop Marcel Lefebvre
Society of St Pius V - Sedevacantist Group
Congregation of Mary Immaculate
Queen (http://www.cmri.org/cmri.htm) - Sedevacantist Group
True Catholic Church (http://www.truecatholic.org/) - Sedevacantist
Group