Biographical information gives life to genealogy data: anecdotes, milestones, major events, personal and professional activities, etc. Local newspapers might focus on particular inhabitants of a neighborhood locale: a business owner, long-time resident, sports figure, contest-winner, maybe a witness to a crime, or perpetrator of a crime. This information can be slapdash and the research very hit or miss, or circuitous - research methods especially demand open-mindedness and creativity. The results merit the effort.
Newspapers often publish the activities of social clubs, charity organizations, fraternal organizations, church groups, occupational guilds, community associations, civic groups, or groups devoted to a specific subject, activity, or hobby, like music, or figure-skating, or collectors of antique microscopes. This is where the stature or fame or prominence of an individual plays no part in why they might end up with their name in print.
Local news is the “known unknown” of genealogy research. Researchers know that they may not know what they may find out about the subject of their research in the newspaper. The more local the locale, the more local the local news. The New York Times is not going to publish an announcement about the new janitorial supply shop that just opened in the neighborhood - but the local Verona-Cedar Grove Times in Essex County, New Jersey will.
Basically, anything that happens: stuff about businesses; crimes; gossip; sports reporting; accidents; etc.
Newspapers in the 19th and 20th century were used as a tool of communication for purposes other than "news." Such "announcements" can take numerous forms, from a paid advertisement, to a posting about a missing person. There may also be cross-over with local news - each are somewhat loose definitions:
Southwestern Christian Advocate (August 10, 1882)
Historical business records often do not exist; if no one associated with the business saved them, or donated them to a research institution, they likely would have just been thrown out. But information about historic businesses, when cross-referenced in city directories, trade journals, or property records, might be found in newspapers. Keyword searching is very hit or miss and it helps to have names or addresses associated with the business. There are many reasons a business might be mentioned—an advertisement, the grand opening, incorporation, closing, a notable event associated with the business, management or employee mentioned in an article or announcement and the business is named; financial information, etc.
It is also recommended to explore the resources and research methods in our division's guide: How to Research A Family Business.