Illinois has relatively little case law on the First Amendment right to anonymous/pseudonymous speech, though a decision is expected soon in Holsten v. Uptown Update and What the Helen. 

One decision, Alton Telegraph v. Illinois, 08-MR-548 (Ill. Cir. Ct. May 15, 2009), deals with whether a newspaper can invoke the Illinois shield law to protect the identity of anonymous commenters.

Maxon v. Ottawa Publishing Co., 3-08-0805 (Ill. App. Ct. June 1, 2010)

Plaintiffs had sought the identities of a pseudonymous commenter that had posted allegedly defamatory statements in comments on articles posted on the website of a local newspaper. The lower court applied a modified version of the Dendrite and Cahill test and dismissed plaintiffs' petition for discovery of the commenter's identity. The appeals court rejected the proposition that "anonymous speech, in and of itself, warrants constitutional protection," and accordingly found that there was "no need for the additional procedural requirements articulated in the Dendrite-Cahill test." Slip op. at 11-12. Instead, the court determined that the only test a lower court should apply to a petition seeking the identity of an anonymous commenter was that set forth in Supreme Court Rule 224, which requires the plaintiff to establish all elements of a claim for defamation. Id. at 13-14. The court specifically rejected any additional requirement to balance the commenter's First Amendment rights, and further rejected the application of a summary judgment standard, rather than a motion to dismiss standard, to test the sufficiency of the plaintiff's claims. Id

AltonTelegraph v. Illinois, 08-MR-548 (Ill. Cir. Ct. May 15, 2009)

In Alton Telegraph v. Illinois, an Illinois trial court denied in part the Alton Telegraph’s motion to quash a subpoena issued by state prosecutors seeking the identity of five pseudonymous posters who commented on a Telegraph story about an ongoing murder investigation. The court rejected the Alton Telegraph’s argument that the pseudonymous commenters were “sources” protected by the Illinois shield law.

While acknowledging in the abstract that commenters could serve as sources, the court ruled that these commenters were not sources because the Telegraph reporter did not use any information supplied by them “in researching, investigating, or writing the article,” and “none of the comments were written until after the article was published.” Slip op. at 5. In the alternative, the court ruled that, even if the shield law did apply to the case, the state had “satisfied its burden to divest the Telegraph of its privilege” because it had exhausted all other sources of information and the sources were relevant. Id. at 6. Nevertheless, the court granted the motion to quash with respect to three of the commenters because their comments did not contain the same highly relevant information and “appear[ed] to be nothing more than conversation/discussion.” Id. at 7.  Neither the court nor the parties raised the issue of the commenters’ First Amendment rights to speak anonymously.