Too many outbound links on a website can deplete a site’s own PageRank (the importance Google assigns to a page based on an automatic calculation that factors in the link structure of the web and many other variables). However, this may be more of a relative than an absolute statement; there are ways to externally link to relevant websites without reducing the importance of your own website.

In its simplest form, PageRank can be explained with this formula:

PR(A)= PR(B) + PR(C) + PR(D)

From the formula above, the sum of the PageRank of pages B, C and D is awarded to page A because all of their links are pointing to A. Basically, pages B, C and D are passing on some of their own “link juice” to Page A.

PageRank is assigned on a page by page basis in that the more outbound links one has on a particular page, the PageRank of the page itself is affected. An intelligent strategy is to create a page on the site that includes a collection of links to websites that your users will find helpful. This is a good idea as externally linking from an internal page on your site as opposed to the homepage will not have that much of an affect on the site as a whole. The homepage typically has the highest PageRank by virtue of the links pointing to it. That PageRank from the homepage flows to the internal pages on the site. So, to keep that healthy internal link structure intact, we’d essentially want to have outbound links coming from a lower level page.

However, all of this can be completely avoided with the nofollow attribute. A few years ago, Google put into action the nofollow attribute so webmasters could link to other websites without losing their own “link juice”. This is useful if a webmaster wants to provide links to other quality websites for their users and not lose their own PageRank status.

One critical component of search engine optimization (SEO) is building links to your website.  These links can be called “inbound links” or “backlinks”.  Although one of the most tedious component of SEO, link building can be the determining factor in having your website position on page one versus page two. It can be what enables you to be differentiated from your competition, possibly even moving your site above theirs in the search results.

To build quality links to your website and to utilize your time most effectively while doing so, it is important to note that not all links to your website are perceived as being equal to the search engines. The SEO value or “link juice” that is passed to your site from a link can be determined by many factors. Below are a few things to look for when establishing a link building program:

Are the links nofollow?
A link that is nofollow is essentially telling the search engines: “Don’t follow this specific link.” This is an HTML attribute that enables webmasters to tell the search engines to not transfer “link juice” (PageRank or anchor text) from these links. The search engine will still technically follow the link.

There a few ways to identify if links are “nofollow”.  First, you can take a look at the page’s source code to see if the nofollow tag (rel=”nofollow”) exists.  Another easy way to determine if a link is nofollow is to install a tool such as the SEO for Firefox plugin. With this, the nofollow links will be highlighted in red.

Does the link come from a page that is restricted in the robots.txt file?
A robots.txt file is uploaded to the root of a website’s domain to tell the search engines to not crawl specific pages on the site.  Therefore, as the search engine will not crawl these pages, links from them will not pass any “link juice” or SEO value to the destination page. 

Redirects can also keep that valuable SEO “link juice” from being transferred through a link. 301 redirects are the most SEO friendly way to tell the search engines that a change of address has occurred for a particular page.  If the page that contains the link is 302 redirected (temporary redirect), the links from this page will not be followed.  There are a few tools out there that can help you to determine how a web page is redirecting and this is one that I use frequently: Rex Swain HTTP Viewer.

There are other things that can prevent “link juice” to be passed from another site to yours, but hopefully these will help to identify the most obvious ones.

For those who are not familiar with www.slideshare.com,  it is a site where you can share PowerPoint presentations with people online.  Using SlideShare can be a great way to promote your business, or to demonstrate products or services to potential clients.  Other benefits from SlideShare include opportunities for link building and more presence in thesearch results.

Slideshare offers users an account where they can upload a profile photo, include information about themselves and include a link to their website.  This profile page contains the link to your site.  It does not have a “no follow” attribute, so you can get some link juice passed to your site from SlideShare once your page is indexed.  It is important to complete all the necessary fields when signing up for an account to get the maximum benefit. 

Once you upload your presentations to SlideShare, you can then get and “embed” code to share your presentations on other sites and blogs.  This embed code also makes it easier for others to share your presentation.

Like many other social media channels, SlideShare has a community section.  This community allows you to share ideas and resources with other users.  You can also have people follow you and follow them back, like you would in Twitter.  Having followers and being involved in the communities can help you to connect with those who are already interested in your products and services.