Also, the on socckread event is reading (in a wrong way but let's assume it's correct) line by line, which is much slower than reading everything at once, you don't need to read line by line:

Code:
 on *:sockopen:newTweet:{
 if ($sockerr) { return }
  sockwrite -n $sockname POST /link/basicSubmit? $+ %tweetmsg HTTP/1.1
  sockwrite -n $sockname Host: clicktotweet.com
  sockwrite -n $sockname Content-Length: $len(%tweetmsg)
  sockwrite -n $sockname Connection: close
  ;-n already sends a $crlf if the data you send doesn't end with a $crlf
  sockwrite -n $sockname
  .fopen -o newtweet tweetread.txt
}

on *:sockread:newTweet:{
  if ($sockerr) {
    .fclose newtweet
    return
  }
  sockread $sock(newtweet).rq &a
  .fwrite -b newtweet &a
}

on *:sockclose:newTweet:{
  .fclose newtweet
  var %tweetID = $remove($read(tweetread.txt,9),location: /basic/)
  echo -s Acquired response from server: www.clicktotweet.com/ $+ %tweetID
  unset %tweetmsg
  remove tweetread.txt
}

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