I just had a look at a website for a new public relations agency that promises to write great press releases and make you famous. I noticed a mistake in punctuation but it wasn't a major error. Then I came across their statement that "we are all journalists so we write from that prospective."
I don't know whether they genuinely don't know the difference between perspective and prospective--maybe it was just a typo. But if you're selling your ability to write (as most of us are), it's an instant confidence-killer.
The moral (which I've violated a few times myself, of course): always have somebody else proofread your work before you send it out--or display it on the internet.
(For great advice on all aspects of writing, get a copy of "Your Writing Coach," published by Nicholas Brealey and available from Amazon and other online and retail sources.)
