Or Pud vs. Ev. Since Metafilter added text ads à la Google, the guys behind FuckedCo and Blogger announced they would introduce micro-ad servers, respectively named httpAds and pyrAds. Makes sense. Update: I'm told I've been a little too eager to compare the two, since in fact Pud mentioned banner ads so far, not text. The too nonetheless share a grassroots "ad serving and buying for the rest of us" feeling.
I just tried to buy 5,000 impressions on Blogger. Everything goes smoothly through the Pyrads server (if you have a Blogger account, it takes 30 seconds and 3 simple screens to fill in), but when I'm trying to pay through Paypal... "The PayPal website is temporarily unavailable due to maintenance. It will be available again at approximately 1:30 am PDT."
The web has to stop looking like it's about to break any time soon, when you least expect it and most need it.
That's where web services and integration will kick in. You don't want users to reach a failure when you send them to your partners, and payment is a critical point since you risk loosing the sale you were about to close. The Paypal web service would communicate its availability to other sites, so they can adapt messages and actions for a better customer experience. Here, Pyrads would say something along the lines of: "we use Paypal for payment, which is unavailable for maintenance at the moment, but should restart at about 1.30 am PDT." The original server wouldn't send its customers to an unexpected failure, and it could use proactive notification (provided by another web service) to get customers back once service is up (ABC: Always Be Closing).
11/27/01 update: BlogSnob, a texbased ad swapping system.
12/21/01 update: Daypop Ad Center.
01/02/02 update: Blogsnob sells its text-ad rotation & exchange PHP script for $40.
01/10/02 update: Textads: A valiant, laudable, righteous – and pointless – idea
01/17/02 update: Will Microads Save Online Content?
02/07/02 update: TextAds, an open source system that "can be run on any Linux based server running PHP, Apache, and MySQL."
02/14/02 update: Advariant Enterprise manages self-serving banner ads on sites such as SF Gate.
03/07/02 update: bombstickers.
03/11/02 update: Ad Farm.
03/13/02 update: text ads on fyuse.
03/15/02 update: Ad Project.net.
08/09/02 update: Orchestrate [web] services.
09/17/02 update: here's a bigger list.