In an unlikely place:
My e-mail address!
A reader contacted me, saying the address kicked back her e-mail. So I looked at it again and ... I confused two of my three e-mail addresses and made an error.
The correct e-mail for me is rb409699####yahoo.com where #### equals the "at" symbol (note: I decided to change this after the first spambot discovered my e-mail on the blog and shot me a junk e-mail).
I proofread everything in Saving My Knees very carefully, except my own e-mail address. Ah well ...