Apple (AAPL) is not a company known for giving things away for free, but when they do, people tend to respond positively. According to a survey conducted for RBC Capital the week after Steve Jobs’ iCloud keynote:

• 76% of respondents said they were likely to sign up for iCloud, Apple’s free e-mail, back-up and data syncing service
• 73% said they were likely to use iMessage, Apple’s answer to the BlackBerry’s messaging service
• Only 30% were likely to sign up for Apple’s iTunes Match service, which costs $24.99 per year

According to RBC’s Mike Abramsky, the response to iCloud among the nearly 1,500 people surveyed translates to 150 million subscribers. That would catapult Apple in the big leagues with such online service providers as Facebook (700 million), Microsoft/Skype (700 million), Twitter (300 million), Yahoo (300 million), and Google/Gmail (200 million).

“Because it stores user data,” Abramsky concludes, “iCloud, along with iTunes, is expected to enhance loyalty and stickiness of Apple’s customers, helping defend against threats from Android, helping grow a defensible install base of users who continually upgrade to next generation Macs, iPhones, iPads, and iPods.”