On the contrary; I find that contributors to comp.arch.embedded and sci.electronics.design manage to produce great input which is clearly written.
The problem with web forums seems to be iphone/ipad accessibility. It takes me 3x longer to write something here using an Ipad, and 10x longer if I have to quote other text. Unless one puts a huge amount of effort into the on-screen keyboard, this results in gibberish and, for those who don't want to write gibberish, loads of meaningless one-liners. All pilot forums suffer from this nowadays.
As regards 7" tablets, I have looked at a few at work and it seems you get what you pay for. The £150 Android ones are just rubbish. One I tried exhibited a 2 second delay from typing to the text appearing
