From Seth Godin’s blog:
Seth’s Blog: On being alert
1. Seth writes a successful ebook(find it here)
2. BRANDPLAY writes a followup to Seth’s book
3. Seth announces it (being alert post above)
4. Seth has the biggest singe day of sales for KnockKnock EVER!
5. Rinse, Repeat
Seth’s mention of BRANDPLAYS book drives sales of his own, original work?
The fact that someone wrote a followup to Seth’s book?