Depends on the topic at hand. The more you would like your opinion considered and understood, the more effort you should put into it. When on a forum, you have the time to check what you've written before you click the button to post it. If it appears you've made an effort, then I'll make an effort to overlook any mistakes made; if it looks like you don't care, I won't either.
Eye halve a spelling chequer
It came with my pea sea,
It plainly marques four my revue
Miss steaks eye kin knot sea.
Eye strike a key and type a word
And weight for it two say,
Weather eye and wring oar write
It shows me strait a weigh.
As soon as a mist ache is maid
It nose bee fore two long,
And eye can put the error rite
Its rare lea ever wrong.
To rite with care is quite a feet
Of witch won should bee proud,
And wee mussed dew the best wee can,
Sew flaw's are knot aloud.
Eye have run this poem threw it
Your sure reel glad two no,
Its letter perfect awl the weigh
My chequer tolled me sew.
It came with my pea sea,
It plainly marques four my revue
Miss steaks eye kin knot sea.
Eye strike a key and type a word
And weight for it two say,
Weather eye and wring oar write
It shows me strait a weigh.
As soon as a mist ache is maid
It nose bee fore two long,
And eye can put the error rite
Its rare lea ever wrong.
To rite with care is quite a feet
Of witch won should bee proud,
And wee mussed dew the best wee can,
Sew flaw's are knot aloud.
Eye have run this poem threw it
Your sure reel glad two no,
Its letter perfect awl the weigh
My chequer tolled me sew.