Significant, because this is an editorial statement from the National Review, and I'd argue the National Review is the closest thing the United States has to a conservative publication of record.
As a moderate-liberal firmly embedded in a very liberal university, I nevertheless think that support for or against SOPA/PIPA falls less on liberal-conservative lines (see, e.g. http://projects.propublica.org/sopa/ ) than some other axis that might be either tech-savvy or might be something like being supported heavily by big-media producers.
It's not too surprising, then, that the other mainstream conservative (or at least conservative-ish) newspaper, The Wall Street Journal, which is owned by News Corp, came out in favor of SOPA/PIPA.
I can't argue with that in general, although I wouldn't describe the folks at the National Review as particularly tech-savvy. I thought their stance was well-reasoned and principled, and avoided a lot of the hype from both sides.
News Corp is an interesting case - they often take conservative stances, and I'm usually a big fan of Peggy Noonan, but they're happy to call for government intervention when it benefits their own business. Not so unusual, I suppose.
"It would be far better to continue to work on technological solutions and to continue the frustrating and thankless chore of pressuring and cajoling our dear friends around the world into deploying their traditional police powers against the worst of the intellectual-property pirates."
If the premium content makers cannot protect their own content then they should figure out how without wrecking the Internet at the expense of the taxpayer. Retrograde bills like SOPA and PIPA impose an enormous negative externality on Internet service providers for the sake of preserving the failing business models of intellectual monopolists, who want the taxpayer to subsidize the cost of production in the Internet age.
The economic woes of the entertainment and news industries stem from longstanding trends that predate piracy on the Internet by decades. Typesetting and printing were expensive operations before the advent of word processing, electronic typesetting and low-cost on-demand publishing. Today, the marginal cost of reproducing digital content is close to zero. The decline in employment in the news, publishing and recording industries reflects the surfeit of digital goods in new media, the efficiencies of computerization and the oversupply of labor. SOPA will not reverse this trend.
