view Web sites whose content is disfavored resembles the burden
that the Supreme Court found unacceptable in Denver, which
invalidated a federal law requiring cable systems operators to
block subscribers' access to channels containing sexually
explicit programming, unless subscribers requested unblocking in
advance. The Court reasoned that "[t]hese restrictions will
prevent programmers from broadcasting to viewers who select
programs day by day (or, through 'surfing,' minute by minute) . .
. ." Denver, 518 U.S. at 754. Similarly, in Fabulous
Associates, the Third Circuit explained that a law preventing
adults from listening to sexually explicit phone messages unless
they applied in advance for access to such messages would burden
adults' receipt of constitutionally protected speech, given
consumers' tendency to purchase such speech on impulse. See
Fabulous Assocs., 896 F.2d at 785 (noting that officers of two
companies that sell access to sexually explicit recorded phone
messages "testified that it is usually 'impulse callers' who
utilize these types of services, and that people will not call if
they must apply for an access code").
In sum, in many cases, as we have noted above, library
patrons who have been wrongly denied access to a Web site will
decline to ask the library to disable the filters so that the
patron can access the Web site. Moreover, even if patrons
requested unblocking every time a site is erroneously blocked,
and even if library staff granted every such request, a public
library's use of blocking software would still impermissibly
burden patrons' access to speech based on its content. The First
Amendment jurisprudence of the Supreme Court and the Third
Circuit makes clear that laws imposing content-based burdens on
access to speech are no less offensive to the First Amendment