'In its latest sales pitch, Dell Canada directs a simple question to students: "Why go to class when you can download the lecture?"

The Web-based advertisement ran for three days last week under the tag line "Dell PCs. The smarter student's choice." It's part of the company's larger Canadian back-to-school campaign.

The ad has roused the ire of some professors. Many now upload their lecture notes on to the Internet, and some even use video podcasts to allow students to download lectures on a computer or play them on an iPod, a PlayStation Portable and some cellphones.

But, they say these services are meant to supplement classroom exchanges, not provide an excuse for students to skip class.

"I hate Dell's message," said Robert Burk, an award-winning chemistry professor at Carleton University. "All of the video-on-demand and podcasting we do for my course is designed as a review tool for students. I emphasize to them regularly that they must come to class, and to use these things only to watch difficult lectures again."

Last year, Prof. Burk became the first professor in the world to release a video podcast of a university credit course. All class lectures, demonstrations and tutorials of his first-year chemistry course are now available globally at no cost.

Dell Canada says the ad is not meant to encourage students to skip class but to reflect the trend toward online education. Distance education, for instance, allows people to work full-time or live a great distance from a school while attending virtual classes on their own time, so there's no actual class to skip.

"Obviously, that wasn't the intention. We would never encourage students not to go to class," said company spokeswoman Wendy Gottsegen. "We wouldn't be happy if anyone construed it like that."

For his part, Prof. Burk is confident his online options aren't turning his students into no-shows. His data show that the average student in his course watches 120% of the lectures -- typically all of them in the classroom and 20% of them again via video-on-demand or iTunes. And many students watch each lecture twice, he says.

Anyone who thinks they can get through the course successfully without attending the classes had better think again.

"Downloading the lecture to the exclusion of coming to class will not bode well for the student's grade," Prof. Burk cautions.

Dell Canada is actually a little ahead of the curve, says University of Saskatchewan student Brad Flavell. Most professors post lecture notes and PowerPoint presentations to course Web sites, but video podcasting is still the exception, he said. Course Web sites are ideal to review material and prepare for a test, but not to replace a lecture, says Mr. Flavell, a fourth-year history student and vice-president of academic affairs at Saskatchewan's student union.

"The technology that we have out there is great ... It allows people to make sure your notes are right, and just look at that as a second glance. It's an excellent study supplementary."'