Learn English – term for negligent spelling of words such as ‘you’ as ‘u’

The age of texting and instant messaging as we all know has created a phenomenon of using shorter versions of words to save on keystrokes. On tiny keypads or phone buttons this obviously can be a time saver. However, in a medium where these shortcuts are not expected (for example, this very Q&A site collection), I find it aggravating and annoying that someone cannot be bothered to type two extra characters for word substitutions such as "u" (you), "r" (are), and "4" (for).

I sometimes want to refer to this activity as something other than "lazy spelling" or "texty-speak…" Is there a term for this type of lazy word substitution?