There are two Talmuds. The Jerusalem Talmud, or Talmud Yerushalmi, was compiled in the academies of the Land of Israel, principally Tiberias and Caesarea, and brought to an abrupt close around 400 CE as Roman pressure on Jewish institutions in Palestine intensified. It covers the first four orders substantially but is incomplete, its Aramaic is harder, and its transmission was poorer. The Babylonian Talmud, Talmud Bavli, was produced in the academies of Sura and Pumbedita and reached broadly its final form around 500 to 600 CE. It is roughly four times the size, its arguments are more developed, and its editing is far more thorough.
The Babylonian became authoritative for most of the Jewish world. The reasons are institutional as much as intellectual: the Babylonian academies survived and flourished under Sasanian and then Islamic rule while the Palestinian centres declined, and the geonim of Babylonia, who answered legal questions for communities from Spain to Persia, taught and cited their own Talmud. Where the two conflict, standard practice follows the Bavli, though the Yerushalmi is consulted and occasionally decides a point.
The physical page is itself an artefact of printing. Daniel Bomberg's Venice edition of 1519-1523 set the layout still in use: the Mishnah and Gemara in a block at the centre, Rashi's eleventh-century running explanation on the inner margin, and Tosafot, the dialectical glosses of his French and German successors, on the outer. Bomberg's foliation became standard, and the Vilna Shas printed by the Widow and Brothers Romm between 1880 and 1886 carried it forward with a large apparatus of further commentaries. Because that edition became the reference, a citation such as Berakhot 28b points to the same words on the same side of the same leaf in any Talmud anywhere.