More than once a dead link has led me to a "Error 404 - Page not found." notice — adorned with "Share" buttons. Any value derived from social bookmarking is wiped out whenever an organization revamps its site without making sure that old URLs redirect to new pages with the original content.
1) A Facebook member is surfing the net. She comes across a great article or video. But there's no Share button. Does the Facebook member say to herself: "Whoa! There's no Share button... I'll reject this." Or will she simply go to her bookmarked member page to let her friends know what she found?
2) A Facebook member is surfing the net. He comes across a totally uninspiring blog post. But a Share button is right there waiting to be clicked. Does the Facebook member say to himself: "This is rather dull. But look! A button. I'll click it, login, and let my friends know I lead such an empty life that even this is better than nothing."
Social bookmarks linking to Pulsed
According to the Google Analytics visitor stats for 'Pulsed' most of the well known social sites have linked to this blog at one time or another. But well over 80% of visitors arrive from search engines.
Share buttons don't boost Google PageRank
Most self-styled SEO 'experts' tell their readers that installing Share buttons will increase their traffic. However, any extra traffic from social bookmarks doesn't guarantee improved search engine rankings. All the well known social networking sites have added the nofollow attribute to users' external links in recent years. But beware! There are plenty of outdated articles online that say otherwise. For example, an article on the Search Engine Journal site lists a few that hadn't done so by 2007, including Digg. Since then, Digg.com and the other well known names have changed their policy. See:
An in-depth analysis of Facebook usage patterns by the social media research company, Sysomos Inc., came to the following conclusion:
The bottom line
If your content is of a high standard, or if you have the latest news on topics lots of people are interested in, you'll get social bookmarks regardless of whether or not you install Share buttons. If your content is unremarkable, buttons are unlikely to boost your traffic.