Sorry, but I'm not buying.
It's not that the information these folks present is bad. Much of it is the same information I provide here on this blog for free. The problem is that there is no guarantee that anyone can help you make your book a bestselling book. The classes or teleseminars might show you how someone else became a bestselling author, but that doesn't necessarily mean you will become one even if you do the exact same things they did. There are a lot of variables to a book becoming a bestseller, such as publicity, demand for the title, the niche market the title serves and last but not least, sales.
Consider this: last year, more than one million different titles were released in the United States. How many of them became bestsellers? Ten percent? One percent? The most recent statistic I could find was one from Publisher's Weekly in 2006. That year, only 200,000 titles were released in the U.S., and fewer than one percent became what would be considered "bestsellers." That is 2,000 titles, out of the hundreds of thousands of books released in the U.S.
There is also the matter of what is considered a "bestseller." There is no industry standard to using the label. There is no set number of books that must be sold before it is considered a bestseller. Also, there are several different "bestseller" lists in existence, but perhaps the most well-known one is the New York Times Bestseller List, but even that list is divided between hardcovers and paperback, fiction and non-fiction, adult and children's books, etc. If an author's book hits the number one sales ranking on Amazon and stays there for one day before plummeting to a rank of 150,000, does that mean it was a bestseller? Some authors and publishers say "yes" without considering the total number of books sold.
The vast majority of books do not become bestsellers, but that doesn't mean they aren't or can't be profitable. There are many titles which provide an income to their publishers and authors and never achieve "bestseller" status. Does that mean they were failures? Heck no!
I would rather see the folks running these "bestseller" classes send out emails that say something the lines of "Learn How to Sell More Books," than "Learn How to Make Your Book a Bestseller!". The first topic would be more realistic. The second topic is wishful thinking. How many authors take these "bestseller" classes or seminars and actually become bestsellers? I'm willing to bet the number is very, very low. If it was as simple as taking a class, publishers would send their marketing representatives (like me) to these classes every year so they can learn the tricks of the bestseller trade. But, they don't.
When I was in the Navy looking to kill time on my ship, I spent many hours reading "The Executioner" series of books...definitely a guilty pleasure. Those books were cranked out every month like clockwork. In fact, at one time you could even subscribe to "The Executioner" series because the books came out so often. Those books were never considered literary masterpieces or NY Times bestsellers, but the 600 novels serialized under "The Executioner" name have sold more than 200 million copies.
The bottom line is don't get hung up on the "bestseller" label. Sure, you want to sell books, and if you sell a lot of them your book may be considered a "bestseller." More than likely, it won't happen as a result of a class, e-book or seminar.