I've read stuff from Raw Story for years. I have Kaspersky, and didn't get any warnings. I'll copy and paste the article for everyone's safety.

With 56% of American Internet connections now capped, advocates ask FCC for probe

The practice of capping Internet bandwidth and selling it as a metered commodity has fully taken hold, to the point where 56 percent of U.S. internet connections are now on plans that restrict how much information users can access before triggering additional fees.

For an Internet landscape that's been accustomed to unlimited access to information the world over, this represents a sea-change for many broadband subscribers. And to at least two prominent Washington, D.C. advocacy groups, it's cause for immense concern.

That's why the directors of Public Knowledge and New America's Open Technology Initiative -- two Washington tech policy groups -- have written to the Federal Communications Commission to request they investigate the potential for these practices encouraging anti-competitive activities.

"These caps, which are now a fact of life for 56% of all broadband users, can perniciously undermine each of the goals set out by the Commission in the National Broadband Plan while at the same time stifling the competition and innovation that has established itself as the sine qua non of the internet economy," they wrote.

AT&T's bandwidth cap for DSL users, which went into effect on May 2, limit users to just 150 gigabytes per month before the fees start piling up. While they claim the limitations are intended to ensure every user has adequate bandwidth at all times, critics say their intent is to force businesses into an artificially restricted business model that commoditizes bandwidth.

"In the world of broadband data caps, the caps recently implemented by AT&T are particularly aggressive," the groups explained. "Unlike competitors whose caps appear to be at least nominally linked to congestions during peak-use periods, AT&T seeks to convert caps into a profit center by charging additional fees to customers who exceed the cap. In addition to concerns raised by broadband caps generally, such a practice produces a perverse incentive for AT&T to avoid raising its cap even as its own capacity expands."

Others have suggested the move by AT&T, which followed a bandwidth capping scheme by Comcast, is also an affront to online movies provider Netflix, which has far and away trumped other video services owned by the network providers. The vast majority of mobile broadband plans are similarly limited, although those caps are typically far more restrictive than home-based broadband.

"The lower cap for DSL customers is especially worrying because one of the traditional selling points of DSL networks is that their dedicated circuit design helps to mitigate the impacts of heavy users on the rest of the network," they continued. "Together, these caps suggest either that AT&T's current network compares poorly to that of a major competitor circa 2008 or that there are non-network-management motivations behind their creation."

"Our usage-based pricing plan is about offering a high-quality, fair and affordable broadband service for all of our customers," an AT&T spokesman told Raw Story. "It is designed to protect the low-volume consumer and provide the high-volume consumer with the necessary information (at least six notifications) prior to being billed for overages. It is narrowly tailored to ensure that only those who use the most bandwidth pay for it. In fact, 98% of our customers will not be impacted by our approach."

Bandwidth capping was explicitly permitted by the FCC's recently-passed "net neutrality" regulations, which mandate that Internet providers treat all traffic equally on wired networks. Critics of the regulations suggest they are really a giveaway to big business and essentially toothless to enforce the rules in cases where the principles of neutrality are violated.

I got no such warning and was able to open the article with no problem.  I think the problem is the article itself, though it's consistent with the view that caps are a nefarious plot.  First of all, of course network operators want to maximize their profits.  They spent billions  to build these new networks.  There also is a legitimate position that a small percentage of users are sopping up huge amounts of capacity to the detriment of most users.  See the attached article for another, perhaps more balanced, view.  Also remember that, despite its name, AT&T is not that big a player in broadband.  The biggest are Comcast, Verizon and Time Warner.

Most likely one of the ads used some code that was more offensive than normal and now it's gone, so the next visitor with the same protection wiuld not see the warning.

People complain because their cable company makes them buy a package of networks, some of which they don't watch.  (Of course, the company has no choice and is contractually obligated by the networks to do this).  But when the cable company offers choice -- in this case to buy more or less bandwidth/speed -- they complain, too.  Makes no sense.

I haven't had to deal with this, but I have a question.
Are the extra prices effected by overall usage, or usage during peak periods through out the day?

I understand that there are limits to what are systems can do, seems to make more sense
(if technological possible) to aim extra charges at times when systems are overloaded instead of a flat monthly limit.  
The guy downloading movies at 330 am for instance might not be putting that much strain on the system, while all the people doing the same thing during prime time are.