We all do it - those of us with websites of course. Well I imagine that most of us do.
When we have a website and something changes, quite often the website is out of step with the organisation. I guess this is because there are so many levels between the web content and the people making the decisions. I would imagine this to be less of a factor in small companies than large because this gap is likely to be smaller. A one-man operation should be fairly up to date whereas a large corporate website is likely to be lagging somewhat behind the times.
Does this matter? I think it does in terms of the impression a visitor gets from a website. For example, I was looking through the Qinetiq website at careers (I'm not moving there but I was asked to apply there once by the head of human factors after a research project I did). Qinetiq are the largest employers of human factors engineers in the UK and do a large number of projects ranging from small to massive.
One aspect of the website interested me: the deadline page which states, "To make things even easier, there are no deadlines on our graduate scheme. Well, when you're looking for up to 150 of the world's top graduates a year, it pays to keep your eye out all the time. So we have a continuous, year-round recruitment policy." (I think the writing needs to change too). All in all, it sounds like a great policy for a company to have: if talented people come along, grab them or they might work for the opposition and you might have to put up with less talented people.
But on another page (detailing the application process), it says, "Our Graduate recruitment campaign for this year has now closed. We are not employing any more graduates at the present time."
Other pages such as the one detailing salaries and benefits is non-existent.
Does all this really matter? Frankly no it doesn't really matter to Qinetiq's work - they are a large enough organisation to get around this easily enough, but it doesn't create a good impression. It is easy to write tools to spider around a site to find dead links and report them to the web developers. Running these automatically can help a company stay up to date. Using effective meta information can also help the developers keep track of all pages that need to be changed when a company policy is altered.