I'm curious what your experience has been using the (two|three|four|five).sentenc.es guides? Do people respond better/worse when you've got that in your email? My thought is most people receiving this message would view it negatively...

i can't say.

i noticed that busy people themselves tend to write very short letters: a pair of questions, no hello/goodbye, nothing personal. seeing that, i started to think that writing five sentences is a respect for their attention and time; i include the disclaimer (signature) to the bottom to indicate that i am not just a dumb, but trying to be short for the recipient's sake.

if they ask specific questions, i elaborate in many sentences (just like i do now :), and then they sometimes don't respond (if we didn't met) or respond after a month (if a person knows me personally). i right imagine how they see the Tolstoy's War and Peace novel, get upset, but as they generally like me, move my lame english masterpiece to some Later folder and move on.

the initial cold emails of any number of sentences stay 90% unanswered.

thrice i shot messages on facebook to the complete strangers that i read about in press (3 sentences: "cograts with new post, would you consider project like ours, if would, i'd be glad to blah blah blah"). and once i got a respond, which forced me to write a long letter which was also answered...

so i dont know if it really works (cold emails are unlucky by nature), but i like to think that being short is a new form of politeness.

(i even tend not to write cold emails at all now! zero sentences, hehe)