[croes]

>the first character is a period and there are other characters on the line, the first character is deleted.

Why is it implemented that way?

If a single period means end of mail then more than a period means it's mail data.

Why deleting the period in the first place? Couldn't they store one byte to check the next?

[wruza]

Cause you have to send a line with a single period somehow.

  .     Ends body
  ..    One period <--
  ...   Two periods
  .A    A
  ..A   .A
  A     A

Anyway that’s stupid and only helps if you compose your email right in a tcp session.