I was keep thinking of something for example i have this: www.site.com And i get backlinks from different sites like this : <a href="http://www.site.com">site</a> an <a href="http://www.site.com/">site</a> Are the second backlinks counted for that keyword or it takes it like a new site?
The anchor text key words should count as long as your not posting on blogs or forums with "do not follow" enabled. Meaning, the owner can turn off an option letting Google know not to count the anchor text as a link. Owners of blogs do this so people won't "Spam" the content on the site.
The only reason it would count as a different site is if you include or leave out the 'www.' - search engines will see this as a sub-domain and therefore a different site
Maybe you should search Google for URL Canalization... and properly decide which copy of your domain you want to use and redirect the other ones to that particular URL using L301 redirection using .htaccess However, to answer your question above.. trailing slash won't case an issue and both links will point to the same domain / URL.
I really don't think it have any effect. I've made SEO for years and saw a lot of self-duplicate issues but never like this one so afiak, That's 100% meaningless.
IMO, they are nothing difference for seo effect . But it is better to keep the link the same . A trailing "/" is not necessary, the browser can add it automaticly when visitors request the site homepage.