SMTP is a text based protocol. I already mentioned that text protocols are evil. It was phrased more nicely in previous posts. Well it can no more be phrased nice. This is stupid! In SMTP it means that binary attachments are encoded using base64 which is part of MIME. Any binary attachment (image, presentation, document, …) you’ve ever sent takes more space in the email. That means it’s slower to send, slower to receive, and wastes more space on the server. The space some people still pay for. I have to remind the reader that such encoding requires additional CPU cycles to handle which in turn increases electricity bills’ totals.
And the additional bonus: ever heard “I have 10M email box but I can’t get an email with 8M attachment from my friend. What’s the problem?”. The correct answer would be the stupidity. Wasted tech support time. They have to explain that 8M attachment can not fit in 10M email box. Try sometime to explain this to someone. Have fun. Extra bonus: Someone pays for this tech support wasted time. Exercise for the reader: figure out who’s paying.
Ilya's blog 
I’ve held this view (text-protocols are absurd) for a long time. What I find most perplexing is that these protocols (HTTP, FTP included) were all conceived in the age where network resources were very lmited.
The only argument I’ve ever heard in support of text protocols is that they are “easy to debug” and even if we were to assume this is at all a valid reason I fail to see how it outweighs the severe performance penalty and furthermore the security vulnerabilities that are rendered applicable by using such a ridiculously complicated encoding.
My only explaination is that these standards were not conjured by anywhere near software engineering (although they most probably were, which is quite depressing)
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