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As an encyclopedia that can be edited at any moment by anyone anywhere, it is possible for a Wikipedia article to be written or produced on a particular current event mere hours, or even minutes, after the event occurs. Unfortunately, the inevitable scramble to add up-to-the-minute information to appropriate articles can often result in something we shall call proseline (pronounced: [ˈpɹoʊzlaɪn])—segments of articles that attempt to be (and should be) prose, but end up looking like timelines. Being comprehensive and up-to-date is perfectly reasonable and okay to a point, but proseline tends to degrade the quality of the articles in which they reside by interrupting the natural flow with unnecessarily choppy sentences and paragraphs.
The origin of proseline 
Proseline typically originates from a scramble to add new information to articles as soon as events happen. An editor normally will not add new information in the form of entire paragraphs or sections because either:
- An editor feels he or she must be first to add this new event and writing a full paragraph would let another editor beat him or her
- An editor does not have the time or desire to elaborate further
Or most commonly:
- There just isn't anything beyond a On Date X, Event Y happened.
Sometimes waiting for a story to develop will prevent proseline (and also false information) from entering articles on Wikipedia, but the tendency to keep Wikipedia current is irresistible to many. If I decide to wait for more information, one thinks, someone else will add it anyway. Thus, I might as well add it myself.
How does one spot proseline? 
There are normally three types of proseline:
- Most often proseline can be detected as a series of one-sentence paragraphs, often containing a date or year.
- Sometimes proseline is a bit sneakier, however, showing up as bulleted lists. This second type of proseline is a problem because we have an unenumerated list where an actual paragraph of prose would do.
- The third form of proseline, and the most difficult to identify, is when a number of sentences within the same paragraph start with a date or year.
At all times, proseline must be identified stylistically, as it is not specific to any particular formatting technique or grammatical construction. (See below.)
What proseline is not 
The endorsement of the elimination of proseline should not translate to an endorsement of the elimination of timelines on Wikipedia. There is no cut-and-dried formula for when timelines are appropriate, but if a vast amount of basic chronological information is available and one takes great care, encyclopedic and informational timelines could be created (see Timeline of the Jyllands-Posten Muhammad cartoons controversy or Timeline of the September 11, 2001 attacks). Perhaps one way to help determine the appropriateness of a timeline is to think about the degree to which the reader will benefit from knowing the exact date, time, and order of events.
Regarding the second form of proseline, it is not a matter of short sentences; concise writing is allowed and encouraged. Writers on Wikipedia, in academia, and elsewhere often make the mistake of believing that long sentences signal knowledge, insight or wisdom on the part of the writer. More often, long sentences indicate poor writing and a lack of clarity. Proseline, on the other hand, can appear in both long and short segments—as an awful example of narrative transition between adjacent reported facts, and a lack of cohesiveness within a given paragraph, section, or article.
What should be done? 
In short, the best way to deal with proseline is to convert it to either prose or a timeline, depending on which is more appropriate. Perhaps you could try combining a section of proseline into paragraph and prose form just to see what happens. For example, note how the second section of this essay could have easily been written in prose:
- There are normally two types of proseline. Most often proseline can be detected as a series of one-sentence paragraphs that each contain a date or year. Sometimes proseline is a bit more sneaky, however, showing up as bulleted lists. This second type of proseline is a problem because we have an unenumerated list where an actual paragraph of prose would do.
In fact, this very section is self-referential, as it is an example of proseline in itself.
Regardless, avoid leaving sections and articles as just series of short sentences without bullets. If a list is beginning to form, make a list with bullets (asterisks [*] in wiki-markup); that contributes to the coherence and organization of the associated article, even if ultimately the section should end up as prose.
Often, the dates included become unimportant when a final resolution occurs. For example, events and stops during a political campaign become less important in an encyclopedia once the election takes place. These small events should then be summarized, removing many or all of the dates.