Okay, I'll admit this is a bit of a rant, but hoping it can be a productive one at that.
With the prevalence of tablets, smart phones, and so on, it seems that people have gotten lazier and lazier in using at least somewhat proper English and spelling. Quite frankly it gets really annoying when you see posts, which consist of:
u in place of you, r in place of are, major spelling errors, cutting off ending (e.g. hangin, likin, lovin, etc.), and "txt speak"
I'm not saying people need to be perfect, and certainly I know I'm not close to it, but it is nice when people at least show they are willing to try. Most browsers I've used have a spell checker, as do smart phones, and if you are on a laptop or computer you can always make a post in Microsoft Word (or Open Office) and use that spell checker.
To the thread title and the hope of turning this into something productive, here is why it is important (in my opinion): When people post in "txt speak" and are throwing major spelling errors all over the place, using U and R, and so on, it gives me the impression that they are either lazy or more likely stupid. In other words it gives off a bad impression compared to people who seem to make an attempt at typing correctly.
You can say it is wrong, but it is just the truth. We don't know everyone, and your persona on here can establish peoples thoughts about you. One of the big things, again my opinion, that effects that is how you post. If you are posting like someone sending a text message (which by the way, typing R instead of are on a phone does not take more time. I type on my phone like I do on here and it doesn't take anymore time then shortening every other word) then it is going to look like you are lazy, or worse stupid, don't care, etc. Just like if you are running around yelling at everyone and calling them jerks is going to make you look..well stupid too and mean/cruel, what have you.
Maybe I'm just weird, but I know peoples post have definitely created an image of them in my head. Maybe they are completely different in real life, but I don't know them there and so what I've collected from their posts is what "they are," so to speak, to me. I wouldn't be shocked if others are the same either.
So to tie back into what I'm saying, you aren't really saving any time talkin like u r ina rush, you are just creating a negative impression to anyone who evens even a little bit of a shit about spelling and grammar. No expects people here to be as good as an English major, or follow the letter of the er..language law by the book, but at least look like you are trying. Yes, there are people who have disabilities which make it difficult. I think though most members understand that and do give plenty of leeway in their errors because they aren't their fault. If you are just too lazy to spell check or type out "you," I feel you shouldn't be given the leeway most give on here already. But it isn't my place, and I think it hurts opinions enough anyways.
Basically, don't be lazy, don't post like you are sending a text to a buddy (and even when you are sending a text to a buddy, it is a good idea to use English there too, just saying) and try to show you kind of care.