Victor, to answer your question about the differences between the Traditional and Modern Mass. The Modern Mass is essentially a modified version of the Lutheran Worship service interpreted under the Catholic lens. The Second Vatican Council Approved the Mass in the 60's to aid in the unification of the Christian Churches. It pretty much became the de facto Mass usage across the Church. Many priests were ordered to stop saying the Traditional Mass.
The modern Mass makes use of the lay people in various forms: lectors, eucharistic ministers, and responses in places that were normally reserved for either the priest alone, the diaconate, or altar servers. Music can be traditional but generally barrows heavily from Contemporary Protestant hymns, 70's soft rock interpretations of Catholic hymns, Tribal Music, Gospel, et cetera. In the Modern Mass, the focus is on the congregants and more recently this strange idea of "fellowship."
The Traditional Mass is basically the Mass that was composed by St. Gregory the Great who was elected Pope in 590ad. Revisions have come and gone, the most significant was the revisions made in the 1500's during the council of Trent which provided the base for the Counter-Reformation, an attempt by the Church to win back congregants that had left with Martin Luther. The last revisions to the Traditional Mass were made in 1962 just prior to the implementation of the Modern Mass.
While both Masses are considered equal, the Modern Mass is phrased as the "Ordinary" form of the Mass and the Traditional Mass is considered "Extraordinary." This is due to the extreme care and reverence taken by priests and congregants participating in the Mass. The musical stylings are limited to Chant, Madrigal, and Organ or Orchestral arrangements. The language usage must come from the Authorized Languages: Latin, Greek, Hebrew, Aramaeic, Church Slavonic, and a handfull of others (language depends on region and Rite). The only usage today in America is Latin and books and pamphlets offer translations so congregants who do not understand Latin are able to follow along.
There are a ton of other revisions such as how the priest stands, how the altar servers assist and how the Eucharist is recieved. The Modern Mass streamlined everything to do as little as possible; though it should be noted that most individuals who have taken the time to learn the Traditional Mass find it to be more sincere and more astetically pleasing. The focus is directly on God and the human condition is viewed more as a selfish vice that reason must dictate, control, and master. While the modern Church often offers trust in feelings and emotions, the Traditional Church warns to be skeptical of how you feel because feelings can be easily manipulated and if left unguarded can prove detrimental to the state of one's individualism.
