The saying goes “don’t put all your eggs in one basket”, however with regards to search engines this is exactly what you want to do.
If you are promoting a page you want to make sure that all your internal and external links point to the same URL. External and internal links need to be working in unison so that the page rank for a particular URL is at its optimum.
The most common example of this is found in home page URL’s. This is an example of a multiple URL:
Your internal and external links should all point to the same URL. If not the page rank will be split between what appear to be two separate pages.
Years ago black hat techniques used to work on the principle, “don’t put all your eggs in one basket”. They would create numerous sites and duplicated pages in the hope that they could dominate the search results.
However as search engines caught onto this they now filter out duplicate content and drop it from their listings. As such the old proverb has now been reversed and it is important that all of your links and marketing efforts are focussed on one page and one URL.
The fix for the common example of the home page URL is to simply ensure all your internal navigation points to the same URL and then sweep up any external links that point to the old URL with a redirect.
Therefore, by having one URL for each page, there is no confusion where external sites link to, giving the site optimum page relevancy and increased chances of rankings.
It goes to show that some old proverbs don’t always work. Especially when it comes to SEO.