Blah...
Just thought I should post this...
JKR said that somthing from book two might become important later in the series...
Things it could be:
1) What Hagrid was doing down Knockturn alley
2) Why Hermione could perform the 'Oculus Repairo' spell outside of school without being expelled
3) The rare and powerful item Lucius did not want to sell in the shop down Knockturn alley...