The dispute over the Naral messages is a skirmish in the larger battle over the question of "net neutrality" — whether carriers or Internet service providers should have a voice in the content they provide to customers.

"This is right at the heart of the problem," said Susan Crawford, a visiting professor at the University of Michigan law school, referring to the treatment of text messages. "The fact that wireless companies can choose to discriminate is very troubling."

The media conglomerate — which is the No. 1 supplier of digital video to Apple's online store, accounting for about 40 percent of downloads — notified Apple of its decision late yesterday, according to a person familiar with the matter who asked for anonymity because negotiations between the companies are confidential.

Today, the Northern Hemisphere sea ice area broke the record for the lowest recorded ice area in recorded history. The new record came a full month before the historic summer minimum typically occurs. There is still a month or more of melt likely this year. It is therefore almost certain that the previous 2005 record will be annihilated by the final 2007 annual minima closer to the end of this summer.

A hammerhead shark that gave birth in a Nebraska aquarium reproduced without mating

At the time of the birth, many scientists thought that the female had mated with another species, or that it had used sperm obtained years before. Female sharks are capable of storing sperm, although none have been known to store it as long as these sharks had been isolated. But through the analysis "it was pretty clear that there was no male contribution," said Mahmood S. Shivji, director of the Guy Harvey Research Institute and author of a paper on the finding being published online today by the journal Biology Letters.

The company said Tuesday that it would expand a test of a system that allows advertisers to pay only when an ad spurs a consumer to take an action, be it purchasing a product, subscribing to a newsletter or signing up to receive a quote from a mortgage broker or car dealer.

The model has long been used online by "affiliate marketing" companies like ValueClick, which have created networks of hundreds or thousands of Web sites that display small ads for e-commerce sites. The publishers are paid when they refer a user who makes a purchase.