What exactly constitutes "Squibdom"?

[Berit Jakobsen]

No: HPFGUIDX 88697

Julie:
> That brings me to this question, and I am hoping for canon evidence 
> (including the extra books, not just the main 5):
> How are Hermione's parents able to go to Diagon Alley?

Berit replies:

Seems they can, as long as they are escorted by a magical person; 
Hermione :-) That's what canon says. It looks like they can see and 
experience the magical place of Diagon Alley when they're there, but 
wouldn't be able to find their way there by themselves (wouldn't spot 
the Leaky Cauldron or its brick wall in the back yard, nor would 
anything happen if they tapped the brick wall I guess).

Berit
http:/home.no.net/berjakob/snape.html