One-sentence paragraphs are OK in moderation.
Some posters here have made a habit of innumerable one-sentence paragraphs.
This becomes annoying after awhile.
Brevity has its limitations.
I have spoken.
The internet is not a book, and cannot be held to the conventions for books. Books evolved over time to give readers the best experience, with spacing a huge factor. Typesetters learned that margins were important, length of lines were important, and leading - the amount of space between lines, was very important.
The internet is still pretty new but most people have learned that imitating books does not work well on screens. Again, spacing is key. Short paragraphs are more easy to read than long ones. People who post blocks of text with no returns get regularly mocked, and for good reason.
Newspapers, as said, learned this before any of us were born. Absolutely nothing new about it.
TL;DR. 
I adhere to the less is more style, especially for online audiences.
I’m retired from my profession and now design websites, social media ads, etc. I’m still amazed how many of my well-educated clients just don’t understand the short attention spans of online browsers.
My worst offender is a physician who used to work for me. I built and maintain three sites for him. Against my advice, he insisted on long, 5-6 word URLs for each site (they barely fit on business cards). Then he insisted on expanding my concise, well-written content into walls of words, filled with medical jargon.
I’m slowly converting him by showing improved traffic analytics when I pare down his content, increase white space, and edit videos down to 15-45 second clips.
If a website doesn’t load and grab the audience’s attention within 2-3 seconds, the majority will click away as quickly as they arrived. Attention spans in today’s digital world continue to shrink.
That is why I used the phrase “fully express an idea,” it captures those circumstances.
But I would go beyond that – even if you want to over-express an idea and use more words than needed. I think that’s beyond the scope of this thread, so I’ll drop it.
Again, the phrase “fully express” covers nuance and any other complexities the writer feels are necessary. Hemingway told Lefty Kreh that good writing is when it can’t be edited any more. Lefty Kreh told Hemingway to stop talking and keep an eye on his indicator.
Ok, then let’s just say I don’t agree with that, or it’s too broad to have any useful meaning.
Jesus wept…
I received advice from a local newspaper editor not long ago advising me to keep my sentences short, even if it resulted in one sentence per paragraph. Since he was my editor at the time, I strove to comply. His reasoning was that readers would be turned off by long, unbroken paragraphs.
But too much white space is wasteful. It seems to be the style nowadays, not only for text, but browser, database and spreadsheet displays. The end product is very little useful data on each page and an increased number of mostly empty pages where a more condensed style would be more efficient.
I find the final result is that viewers, who often seem to be ignorant of scroll functions and are viewing the post on a tiny, portable device, completely ignore anything that extends past the first 5 data lines. It’s a disappointing trend.
Ok, let’s say that.
An author may also change voice within a piece. One character may be terse where another is verbose, for instance. Or one might choose punchy structure for an intro and conclusion, with slightly longer form for the meaty bits in between.
Five sentences “minimum” for a paragraph is bizarre - it leads to walls of text where you miss everything in the middle.
I used to teach paragraphs using the TiP ToP method:
Ti = Time
P = Place
To = Topic
P = Person, including giving each speaker a new paragraph.
It’s pretty much faultless. Good writers know those rules intrinsically and break them for a reason, bad writers just keep on writing and then eventually hit the return key.
Endless one-line paragraphs are annoying and can be hard to read because they break things up too much, but at least they’re better than the wall o’ text.
What’s the deal with using “are comprised with” when you mean “are composed of” instead of “were included in”? It seems this is a recent trend. I find it annoying.
Are we now off on random linguistic peeves?
OK, I’ll address this. I’ll use multiple short points and paragraphs.
“Are comprised with” is non-standard English. Pedants would simply say it’s “wrong”. Because it is.
“Are composed of” is appropriate, if that’s what is actually means.
No, “were included in” is not equivalent to “composed of”. “Composed of” tends to imply an observation of a natural phenomenon: “water molecules are composed of hydrogen and oxygen atoms”. “Were included in” is more like a description of a marketing decision: “Several common drill bits and an extra battery were included in the cordless drill package”.
One online game I play has several chat channels, and people there can get moderated (warning, then bans) for using the enter key as a space bar. Where the chat is spammed with lots of little messages that all could have been grouped into a still small paragraph.
First, I obeyed Muphry’s Law by saying “were included in” rather than “included.”
Second, we are not off on random linguistic peeves; we are observing that the OP complained about one aspect of language while not following the level of discipline he seems to insist upon.
My theory: The increasing trend toward short one-or-two-sentence paragraphs is in response to the increasingly deteriorating attention-span of the “average” American reader.