Read more here (learnstuff.com)
I know that giving out customer information to third parties is an extremely unethical business practice and I'm pretty sure that it is in violation of Canada's privacy laws!
What can you do about this? A slashdotter has kindly posted an excerpt from Videotron's Customer Service Agreement:
12.4 Protection of personal information - The personal information supplied by the customer to Vidéotron shall be treated in accordance with Videotron's policy on the protection of personal information, which is available upon request at Videotron's customer service by telephone or at: email@example.com.
If you have to use a major Internet access company in Canada then avoid Videotron by any means necessary. Use any one of Canada's other major Internet access companies including Shaw, Rogers, Sympatico or Telus. These companies are actually fighting the CRIA in the courts to protect your privacy rights instead of happily giving them away.