What counts as an expression on a matter of public interest under Ontario's anti-SLAPP law?

Courts interpret public interest broadly for anti-SLAPP purposes - it is not limited to political or government matters, and can include commentary on businesses, consumer experiences, professional conduct, community issues, or anything a segment of the public would genuinely have a stake in knowing about or discussing, not just topics that are inherently important or newsworthy in a traditional sense. The focus at this stage is on whether the subject matter itself is of public interest, not on whether the specific statement was true, fair, or well-researched.

Those questions about the quality of the statement come later, in the second stage of the test, not in deciding whether the initial threshold is met at all. Purely private disputes with no broader public dimension - a personal grievance between two people with no wider relevance to anyone else - generally will not qualify, but courts have been willing to find public interest in a surprisingly wide range of everyday commentary, including online reviews and social media posts about local businesses or public figures.