I've met and worked with many people who think that just because it is being read through a computer that they don't have to read it carefully.
As a so-called 'digital native' with an unapologetic love for text, I find it extremely frustrating that people don't take online text seriously. Some people even like to speed-read, racing through text faster than they can recall the pronunciation of the words.
You might think you can speed read and still understand the content - most of the speedreaders I know hold that belief quite dear - but you aren't getting the whole story. A single missed word can profoundly alter the meaning of a sentence. I've seen many conflicts and miscommunications caused by lazy reading and misinterpreted messages.
If I took my time to write a clear, concise, meaningful message/email/post/document/etc, please pay me the courtesy of truly reading it.
/rant