Dumbledore in GoF

[starboard_7]

No: HPFGUIDX 78663

I was recently rereading GoF for the 10th or so time, and something 
stuck out to me that I hadn't noticed before...

Towards the end of Goblet of Fire, after Harry returns from the 
Portkey back to Hogwarts, he is talking to Dumbledore (who just 
discovered Mad Eye Moody, etc).  Harry tells Dumbledore that 
Voldemort had gotten some of his [Harry's] blood and consequently 
now has the same protection Harry has from his mother.  After 
learning this, Rowling writes (not exact quote) that Dumbledore 
seemed to smile for a fleeting instant before responding that 
Voldemort has "overcome that obstacle."

Did anyone else wonder what this could mean?  I noticed it about 5 
days ago and it has been bothering me a great deal...
I'd love to hear others' thoughts about it.

"starboard_7"