The Facts About Link Building
We know that Google says that you should never buy links to help your ranking, or build links in any "unnatural" way. Everything should be "organic" and "natural", blah blah blah.
But we also all know that very, very few of the sites ranking for big money keywords are doing everything organically and naturally. They all buy backlinks. They all build backlinks.
Especially for more competitive search terms, the bottom line is you have to be building backlinks regardless of what Google has to say about whether or not that's acceptable. Well, you don't have to, but if you want to rank in Google you do.
These are the facts.
So how can you make your links "safe" in Google's eyes?
301 Redirection Is Your Friend
Google states publicly that if you want to move content to a new location you can use a 301 redirect. A 301 redirect is a command that tells whoever is accessing the page that it has moved permnently.
Since Google understands that sometimes content has to be moved, any links aimed at the old location are also counted toward the ranking of the new location.
It's on these facts that we can build our linking "safety net".
If you have a site that's very important to you, and you want to try and be more aggressive with your link building to see if you can improve your ranking, don't link directly to the page you want to rank.
Instead, link to a "buffer" page on a different domain that 301 redirects to the actual "money" page. If those links cause your site's ranking to improve, great! Success is yours. But if for any reason those links actually hurt your ranking -- just delete the redirecting page off of the buffer site.
It may take a few days (or even up to a few weeks), but Google will eventually remove the dropped links from affecting your money site/page.
How To Create a 301 Redirecting Page
Creating a 301 redirecting page is simple. A few lines of PHP code is all it takes:
header("HTTP/1.1 301 Moved Permanently");
Just copy/paste the code above into a file with the extension .php (for example, myrediretpage.php) and upload it to your buffer site. Then create your backlinks aimed at that page instead of directly to the money page.
There are a couple of downsides to this method. For one thing, you have to pay for the hosting and domain registration of a new site. That's pretty inexpensive, though, especially compared to a severe drop in rankings if you get it wrong.
To be extra safe, you need to use a different buffer site for every money site you use this method on (rather than just uploading a ton of redirecting pages to one buffer site). That can get expensive -- but again, it all depends on how much you stand to lose.
Real World SEO
It would be great to live in a world where Google didn't constantly say they want one thing ("natural" links) while always rewarding those who do the other thing (buying/building links), but we don't live in that world.
Until we do, this is one method you can use to ensure your money site is "safe" from Google's next change where the links they used to be okay with are no longer considered ok, and what used to work no longer works.
Worst case scenario you could always just delete the buffer site entirely and wait for Google to recrawl and realize all of those redirects are gone. In time your money site will go back to having a "squeaky clean" link profile and you can start over again without having to give up your well-branded domain name and all of the awesome content you've worked so hard on.
Here's to your success!