IRS Publication 936, subheading "Fully deductible interest", category #2 says:

"2. Mortgages you took out after October 13, 1987, to buy, build, or improve your home (called home acquisition debt), but only if throughout 2006 these mortgages......"

My question is: if a first-time home buyer takes out a first mortgage (home acquisition debt) in 2007, will the "throughout 2006" mean "throughout 2007"?

IRS Publication 936, subheading "Fully deductible interest", category #2 says:

"2. Mortgages you took out after October 13, 1987, to buy, build, or improve your home (called home acquisition debt), but only if throughout 2006 these mortgages......"

My question is: if a first-time home buyer takes out a first mortgage (home acquisition debt) in 2007, will the "throughout 2006" mean "throughout 2007"?
YES

Agreed; it is likely the IRS Pub 936 applies to the 2006 tax year and has yet to be updated.