> Legally, they can't give money directly to candidates or even coordinate with them. Only traditional PACs can do that.
Pretty sure I covered that point.
> Giving ad time or ad space directly to candidates, as Joel proposes
He didn't actually say that. He said giving ad space to a 'political campaign'. Spolsky also, and quite rightly I think, steers clear of the idea of tech companies directly spruiking friendly candidates. But you could have a PAC whose sole function was to allocate ad inventory evenly between a disparate field of candidates, for example. Google could even run it algorithmically off their own system.
There are lots of ways to do it and, as demonstrated, no real regulatory barriers. The only thing missing is political commitment on the part of internet companies. I agree with Spolsky that there is huge untapped power in this idea. I'm just not sure that it would be beneficial to society over the long term to have it unleashed.