Like you I immediately thought of the recent ageism articles on HN and specifically PG's comment about the "cut off" age for consideration for tech-investors being 32.
I think it's only 32 if you're relatively unknown or unproven. If you're Biz Stone, raising outside financing (in addition to your own cash) shouldn't be a huge barrier. Likewise, I doubt Uri will have a hard time with that 32-year cutoff now that he's had a $1.1 billion exit.
What a silly thing to have a 'cut off' age for techies. Like a good Single Malt or Wine, we get better and better with time. Age delivers on certain pragmatism not found in the youth of today :)