martinibuster - 5:40 pm on Mar 8, 2013 (gmt 0)
SEOPTI makes an important point about general advice not being applicable to specific web pages. The variety of web pages makes it difficult to apply general advice. Perhaps the AdSense program should take this as constructive criticism for improving their outreach to more accurately help its publishers.
For example, the advice for more blocks, as someone already mentioned, makes sense on a long article page. On shorter pages then two ad blocks and a text link block at the bottom can be optimal.
The point about ad blindness is also true. I've experienced a drop in earnings caused by the addition of another ad (in this case an Amazon ad unit). So I removed the Amazon ad to restore the previous pattern.