The internet is a great forum to cultivate ADD habits. Most people using it get bored very quickly. A big reason why a lot of websites start out good but then fall off the radar is that they are not updated. Websites need to be updated regularly. That doesn’t mean that you need to constantly add new content every second. But it does mean that it heavily depends on your industry.
Depending on whatever industry your business is a part of, you’ll need to update your website daily, weekly, monthly, or whatever consumers of your industry demand (aren’t we all at the mercy of our customers). But beware, once you start updating your content more quickly, your site visitors will expect the content to be updated in that same frequency for the rest of your site’s lifespan. So be like the tortoise, start out slow and pace yourself. You can regularly update your site with new content such as pics, videos, or even text. That way, your regular visitors won’t abandon your site completely.
Here’s someone else who thinks so as well: http://wordsyouwant.wordpress.com/2008/09/01/why-updating-websites-is-important/