Lots of posts moaning about how posts are worded so >>
Aoccdrnig to rscheearch at an Elingsh uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht frist and lsat ltteer are at the rghit pcelas. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae we do not raed ervey lteter by it slef but the wrod as a wlohe.
that when reading rapidly we look at the 'shape' of the word, and that's why lots of people miss typos when they're writing largish blocks of text.
An editor, reading the text for the first time, isn't so familiar with the content so he/she reads more slowly, and with greater attention to word construction - so he/she should spot typos quite easily.
This refers to spelling only. The situation with poor grammar and faulty or missing punctuation is that the entire meaning of text can be changed by a word in the wrong place (whether or not it is spelled correctly) or, similarly, by a punctuation mark (; : . , et cetera) being wrongly placed or omitted.