In many areas of the country (leaving aside what may be found overseas - that's for another time), newspapers have been published since the earliest times of their settlement. Naturally, the 13 colonies are more likely to have regularly published papers than smaller, more lately settled regions.
But the importance of these sources cannot be overstated. I speak mostly from my own professional experience and research trips. Old newspapers, whether they were daily, weekly, or monthly; local, regional, or otherwise in scope, they contain not only news items such as happens every day, but also note births, marriages, and deaths; personality articles, articles on businesses, churches and social clubs, military services, and so on.
My own library in Rochester can serve as an example. Your mileage, of course, will vary depending on your location and needs. We have all of our locally published papers from 1818 - the year that our town was incorporated - down to the present. That's nearly 190 years. We also have many, if not all, of the suburban papers, which tend to have started about the 1920s or 1930s in our area.
The city papers include the items mentioned above. And there was not just one - at times, there were six or more newspapers, and they had different takes on occurrences. One recent research case showed a man's obituary very simply printed in five papers. The sixth must have really hated him, because the obit ran on for many column inches, pointing out his, and his family's, shortcomings! Good thing that he had passed away and didn't have to read it. But the long, uncomplimentary obit had a wealth of facts about the family. Since he had died childless, the comments about the family and their occupations, lawsuits, and happenstances were a gold mine of information for the researcher.
The way we access this, for the most part, is through an 85-volume, 500,000 item newspapers index. Other libraries have similar indexes or card files. Hold on to your seats - we will be digitizing the index (NOT the underlying newspapers, as that would be a phenomenally labor intensive undertaking) and making it available on the web. We will obviously advertise this when it is ready. Plus, we have a room full of clippings sorted by name and occupation, among other things, estimated to be 4 million clippings, and dating from 1936 to date. That's when our library first opened. Before you write or call - the clipped papers are NOT indexed and have to be searched by hand. We do welcome visitors, but cannot do a search for you. Also, we are indexing our biography and obituary scrapbooks, and are somewhere north of 120,000 names in those, as well. Yes, we have got quite a stash of information for you, for free (well, to look at), and so do many other libraries. Ask them!
Suburban papers, especially in the 20th century, do a better job of printing scholastic accomplishments, obits of long time residents, etc, than do the larger city papers, for whom a town resident is of less consequence. Look in the surrounding area of a location. However, there are, especially in the 19th century but not limited to it, other papers which will print out of town obits or marriages. Some entries in the Gem and Ladies Amulet in our area, for the 1820s and 1830s, cover events items from 200 miles away. There's no rhyme or reason as to what may or may not be included.
Some news items are reprinted in commercial databases or genealogy club newsletters. Many, if not all, of the original papers are on microfilm or have been scanned, so be prepared for various formats. Some papers are very good with typefaces and readable print, as well as predictable locations for pages of interest; many are haphazard. Expect variations.
So what will you find? Mostly deaths, some marriages, some personality articles, some industrial employees items, some church notices and sports items; and even criminal (victim or perpetrator) items. It's reality and history. People are what they are. Be prepared to be proud - or surprised.
Here's a national example. The New England Historic Genealogical Society recently added a valuable item to its collection of online databases. This is described in an article on their site called "The Search for Missing Friends: Irish Immigrant Advertisements Placed in The Boston Pilot 1831-1920" ([[http://www.newenglandancestors.org/research/Database/MissingFriends_VOL1-8/Default.asp|http://www.newenglandancestors.org/research/Database/MissingFriends_VOL1-8/Default.asp). What it is, is nearly a century of "where are you" ads placed by relatives trying to find one another after they had emigrated to America. It can contain much data about the immigration as well as who is looking for whom, and their relation. I would encourage you to seek this out in general and especially if you are researching Irish ancestors.
Do beware of writing to organizations which charge an exorbitant fee for searching and copying. Our own library has had fees set by the board of trustees. While we are not dirt cheap (about five to ten dollars, depending on the request), it is less than the hundreds (yes, hundreds) of dollars wanted by some local organizations. Ask before you order. And don't call or write to a library or archive with a time-sensitive request ("I'm having a reunion this weekend. Send me everything"), nor expect a page-by-page search. Staffers in these organizations are good, but they are not miracle workers. Librarians provide reference and referral; paid researchers can be more flexible about such requests.
We are aware of many fine organizations which can provide similar functions, but we feel that a public library should have free access and modest fees. Contact your local or research area library for their particular holdings and policies - they vary, as you would expect. Happy hunting.