Personally, I feel it is very important. If you are sending a letter or email to someone you wish to impress (such as a future employer) then it is essential.

I think it is very important. The grammar and spelling in a piece of writing can make all the difference to it's meaning.

Must not be that important if athletes still make it to the pros using words like "mouf" (mouth) and "bafroom" (bathroom).
Pretty pathetic if you ask me
IN OTHER WORDS, EXTREMELY IMPORTANT.
BECAUSE OWNERS OF PROFESSIONAL SPORTS TEAMS NEEDED PARTICULAR PLAYERS IN ORDER TO IMPROVE THEIR REVENUE, GRAMMAR AND SPELLING BECAME IRRELEVANT...
I STATE A FACT AND STILL GET A THUMBS DOWN. NOW THAT IS PRETTY PATHETIC.

It's important to write in a way that people can easily understand: after all, the point of writing is to communicate with other people.

Having a 'correct' way to spell a word helps. Think of words that sound the same but are spelled differently, like 'rein', 'rain' and 'reign': the spelling tells you the meaning. Yes, it might be possible to work it out from the context, but it would take longer. Grammar's the same. You might be able to work out what someone meant if their grammar wasn't clear, but equally you might get it wrong.

For me, using standard grammar and spelling is a way of being polite to my readers, because I think it helps to make what I write easier to understand.

(I prefer to think of it as 'standard' grammar and spelling rather than 'correct'. There are a couple of reasons for this. One is that 'correct' suggests that there's a committee somewhere laying down the law about it. Actually, grammar and spelling evolve from usage, and therefore change as time passes. Another reason is that there can be different 'correct' versions, particularly with spelling: 'focused' and 'focussed', for example.)

It has to be very important i do not understand how the youth of today get jobs with computers because the can not spell and they talk in a different language to my generation.

Very important. The standards have dropped considerably. I love the way 'older educated people' speak because they were taught to speak and write properly.

Sometimes I think we sound like a mob of derro's because the standard of our speech and writing has decreased considerably

Geez, I hope that sounds ok - I'm all nervous now!!! lol

Very important! Judging by the bad grammar and spelling in some of the questions in here, it seems the ability to communicate in intelligible English is becoming a dying art.

The fact there are a lot of responses on here indicating that these things are still important, however, gives me great hope.

My pet hate is the misused apostrophe...