Indiana law defines as business pursuit as "a continued or regular activity for the purpose of earning a livelihood." Mid-American Fire & Casualty Co. v. Shoneys, 843 N.E.2d 548 (Ind. App. 2006). CMLP has identified no Indiana cases interpreting this test in the context of online publishing out of the home (or elsewhere).
One Indiana court has held that the a for-profit activity is not a business pursuit if it does not occur continually or regularly, or if making a profit is not the primary motivation. See American Family Mutual Insurance Co. v. Bentley, 352 N.E.2d 860 (Ind. App. 1976). In that case, the insured rented storage space in his home to a third party for money, but there was no evidence that he did so regularly, or that profit was his primary motivation. In other cases, however, Indiana courts have held that an activity is a business pursuit even if the activity is not the insured's primary occupation. See for example the Shoneys case above.
Therefore, if you live in Indiana, you may be in danger of losing coverage for your online publishing activities if you make money from your website or blog, such as through advertisements or a tip jar, unless those activities are temporary or sporadic.
Note that specific language in a policy might lead a court to a result different from the overall state trend.