To Cache or Not to Cache


To read last week's press accounts of how Comcast Corp. was monitoring its cable-modem users' surfing activities in order to speed up access time to popular sites, you would think the MSO posed a terrorist threat to Internet security.

That was hardly the case, since Comcast immediately changed its practices. But the very public fracas raised some disturbing questions about what Internet-service providers are — or are not — doing to protect their customers' online privacy, if you even believe there is such a thing. I don't.

It's so much the case that last week in The New York Times, an attorney for the Electronic Privacy Information Center said the Comcast episode is "the Internet-privacy horror story that everyone is concerned about."

The "horror" was not that Comcast and other ISPs routinely track such information. It was that the method Comcast used to do the tracking would allow law-enforcement agencies to subpoena the MSO for information about its customers' online activities.

In our page-one account of Comcast's woes — a tale that attracted the attention of politicians and the national media —Broadband Week
senior editor Karen Brown spells out how Comcast's method of tracking subscribers' Web activities differs vastly from those used by other ISPs.

As Brown reports, just about every ISP uses cache servers to store content at the rim of its network in order to speed the delivery of popular Web sites to its users. So why did Comcast's approach stand out like a sore thumb and raise so much ire? Because it tied the customer's specific Internet-protocol address directly to the Web sites they visited.

That's taboo. It's also not the way other ISPs run their businesses. For instance, AT&T Broadband's high-speed ISP doesn't track in a way that links the user's IP address directly to their destination. AT&T can tell how many of its cable-modem users visit, say,, but it can't match those raw numbers to specific ISP addresses.

America Online — the nation's largest ISP — follows the same policy.

Somewhat surprisingly, at least to me, was that Cox Communications Inc. sees absolutely no merit in caching content at all. The folks at Cox think caching content adds a lot of overhead to keep things humming along "squeaky clean," and provides little benefit.

That's an interesting point of view that begs the question, is caching worth the grief? Yes and no. On my creaky dial-up AOL service at home, caching makes a huge difference in quickly getting to a popular destination like Ebay.

But does it really make such a difference on a T1 line, digital subscriber line or cable modem? I wonder. I don't have the answers, but I doubt it.

I've always been leery of popular cached destinations like Ebay. You get there quickly, and then the electronic cookies start coming your way.

Questions like, "Do you want to store your password?" pop up, allowing you to go even faster. And that's neat if you're in the heat of an Ebay auction, where seconds can count.

But anyone who ever took a "cookie" from a stranger knows what happens next. The electronic-mail onslaught is non-stop. And that's another form of invasion of privacy.

Maybe Cox has the best solution. Why cache at all, if you don't need to? Presumably the main benefit of the cable modem is high speed, and that's what it provides.

Isn't that enough?