Outbound links (websites that point to your website from other websites) negatively affect your PageRank. But in general, people say that it’s not difficult to get good outbound links. You should only do it when you think that doing so makes sense. Don’t worry too much about your PageRank. I agree with that. If you have a lot of links that point to other websites, that will cause your page rank to decrease. Because of how many factors determine what page ranks well, you should be focusing mainly on generating quality content. That includes good outbound links. I want to highlight two very important differences between outbound and internal references.
- If you want to include many links to other websites, try to place as many links as possible (or as few pages as possible) to other websites.
- If many pages within your website have very little relevant content, try to link to many of them (if possible) on as few pages as possible.
I have come to this conclusion after studying the formula that determines what PageRank is. It’s a bit of a math story, but the concept is very simple: Several factors determine the PageRank of a page, but they all come down to this: Generally speaking, pages that are referred to from one page can pass their PageRank to the pages that are referred to. If all those links point to your site, the PageRank will be raised. If there are other outbound links to your page, it will be at the expense of the PageRank of your site. This will be obvious, but we need to know how to minimize the loss of PageRank from outbound references.
Here is a look at the PageRank formula. It shows that if you have many pages pointing to other websites, they will have more PageRank than you do. If a page refers to another page on the web (outbound or internal), then its PageRank is lost. If there are three references, that is 1/2 of the PageRank of the referring page. If there are two references, it is as though the entire page rank of that page is given away to the page where the reference is. If there are three references, it is as though there is half a page rank given away to the other page. It seems that the PageRank that is lost due to an extra link is becoming smaller and smaller each day. It is difficult to know how much a given page’s PageRank loses because of extra references to other pages. In simple terms, it’s nonlinear.
The loss of PageRank is therefore relatively small if you can bundle links to other websites that are not relevant to your website, and that means a very small number of pages. That applies to outbound links and internal links to pages that have very little relevant content. Because of the nonlinearity of the formula, you will be losing relatively little PageRank.
If you optimize your website very carefully, you will not gain PageRank from outbound links. However, you can still benefit from using this knowledge when making decisions about the structure of your website.
Last, if you omit the rel=nofollow in the link text, all PageRank traffic can be blocked. The above advice is given in cases where you do not want to block a site because the information on the other page is no longer relevant. It may be that people have asked you to block a site when this happens. Sometimes, you want to give something as a gesture of goodwill to someone you trust. It is the nature of the Internet that allows people to give away a lot of PageRank.