Also, looking though the patch notes to try and find when Razor was changed, I have realized 6.55 was likely the most significant patch to making Dota what it is today:
http://www.playdota.com/changelogs/6.55
1) Added Captains Mode to the game.
2) Made TP scroll what it is today. Before only one person could TP to a building at a time and it gave bonus armor. This made it where the entire team could TP to a single spot.
3) Added Glyph of Fortification
4) Gave BKB its scaling duration, and rehulled the recipe to be what it is today.
5) Added Dust, Magic Stick, and Phase Boots to the game
6) Added Windrunner and Kunnka, and Made Keeper of the Light and Enchantress what they are today.
That was October 7th 2008. So the 5th Anniversary of Captains mode is coming up soon!
Also, Razor was reworked in 6.60, which came out June 11, 2009.