Hi there
I am not entirely sure I have ever heard that rule before - can you source that?
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First, you have to figure out if the links are follow or nofollow. Follow meaning they pass value or nofollow meaning that more often than not, they don't. There's a common misconception that you only want follow links - this is simply not true. Even if a link is a nofollow link or not passing any equity, it's still potentially valuable from multiple standpoints. All links can provide value, by the way, it's not limited to just one link.
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Yes, if where the backlink is pointing to is relevant to the content on your website. For instance, if the link is linking from a page about lawn mowers to a page on your site about toaster ovens, I wouldn't consider that a valuable link because it's not relevant. Does that make sense?
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I suggest you read Google's stance on link schemes, as paid links are something that they have heavily cracked down on. I would suggest that you nofollow the link pointing to your website to avoid any unintended repercussions. I would also suggest you take a look at this Whiteboard Friday post to learn more about how paid media investments can have SEO value - you just have to be smart about it!
I have to say this though - don't "link build" with the intention of boosting rankings. I know that's an odd thought but you have to remember that any link you acquire should be done with the intention of adding value to that link and the user that is arriving because of it. Stay away from heavy anchor text or site-wide backlinks as you could obtain a manual action for attempting to manipulate Google's algorithm.
I also suggest you read Moz's The Beginner's Guide to Link Building - there are a ton of great resources and tactics in there that can help you stay on the right side of the track.
Hope this all helps! Good luck!