Cardcaptors vs Cardcaptor Sakura
When WB purchased the licence to CardCaptor Sakura, they had a particular target audience in mind. Nelvana was contracted to format the series for younger viewers of both genders with an action and magical story slant instead of the percieved only female target.
Complicated episodes or moments that could upset very young children were cut, the incantations and names were changed to sound less foreign and various character "crushes" were removed.
The problem is that, all over the world, whereever CCSakura has been shown, it has appealed to an older public. Older public that felt betrayed by WB/Nelvana when they found out about the longer, deeper, original version.
The differences are:
A focus on two main heros (one boy, one girl) instead of just Sakura.
A different episode order with some episodes skipped.
Slightly different personalities for the characters and different voice types. Tomoyo's gentle voice was changed to a "valley girl" accent for example and Kero while competitive in both versions also shows a softer side in the original.
Sequences that feature sad moments, a deeper intrigue or Sakura and Syaoran admiring Kaho or Yukito are cut out.
The japanese names were changed to american equivalents.
Theme tunes and insert songs were replaced with new material.
For a lot more information on this subject, please visit Heidi's CCS vs CC.com