Who published the first newspaper?
The first newspapers were nothing like papers today. They were more like letters containing news. In the fifth century B.C., there were men in Rome who wrote newsletters of current Roman affairs and sent them out to the various territories and towns of the empire. Ferried by running messengers, these "newspapers" were really just 2-3 page documents that covered all of the recent news and events in the capital. What makes this different from regular correspondence is that the receivers were discouraged from writing back to the source. Also, everyone received copies of the same document.
A news source more similar to our current newspaper was established by Julius Caesar in 60 B.C. He had the government publish a daily bulletin for posting around the outside of the Forum that recapped the previous day's events, conflicts, and resolutions. Devoted chiefly to the governmental announcements, the paper was named Acta Diurna, which meant "Daily Happenings."
One of the chief needs for getting news quickly in the early days was for business purposes. Businessmen had to know what important things had happened, and were going to happen. Therefore, one of the first newspapers/newsletters was started in the sixteenth century by the Fuggers, a famous German family of international bankers. They established a system of gathering news from multiple sources to help suppress inaccuracies, and make the news more reliable.
In Venice, at about the same time, people paid a fee of one gazeta to read notices that were issued by the government every day. These were called Notizie Scritte ("Written News"). Eventually, the price for the news went down, and more and more people could afford to read them. Therefore, the government made the notices into a booklet that was printed bi-daily.
The first regular newspaper established in London was the Intelligencer in 1663. Most early papers (including the Intelligencer) were only published once or twice a week, because both communication and production were slow.
The first American newspaper, Publik Occurrences SIC, was started in Boston in 1690, but the governor of the colony stopped its production within a month. One article they printed revealed (and ruined) the personal life of a high-powered official (one source says it was a secretary, one says it was the military advisor for the governor). In addition to having the paper shut down, the chief editor was fined $900, a lot of money in that time. Also, the author of the article was jailed, and never heard from again.
Benjamin Franklin conducted the Pennsylvania Gazette from 1729 to 1765. The people were so eager to have newspapers that by the time of the American Revolution, there were 37 major ones being published in the Colonies!
One of the most influential newspapers ever published is the London Times, which began in 1785 under the name of the Daily Universal Register. It is still published today, and has a daily printing in English, Scottish, French, Spanish, German, and Irish.
Sources:
Letters and Literature, by Harper Press (English textbook, main source)
The Big Book of Tell Me Why, by Arkady Leokum (secondary source)
The (London) Times Online, which can be found at http://www.the-times.co.uk/