#1 Link Building with “Rented” Paid Links
Nowadays, paid links are strictly forbidden by Google. However, once upon a time, link purchasing was the lifeblood of black- and grey-hat SEO. It was effective and cost-efficient.
Basically, “rented” or brokered paid links are links that you use for a limited period of time. When your “rent period” is over, you can either rent the links again or they’ll go back on the market for other SEO ninjas to purchase and use them for their sites.
Obviously, this can be seen as cheating. SEO pros could keep their clients on a tight leash, making sure that they would never get rankings high enough to stop investing in links. For the better, Google put a stop to that kind of cheating.
#2 Use of Paid Permanent Links
The followers of House Paid Permanent Links believed in “high-quality search engine optimization” (Yeah, that’s what they called it). By high-quality, they meant that “rented” links were not an option. Instead, they focused on purchasing paid permalinks: links that you pay for once and use permanently.
To tell the truth, House Paid Permanent Links was a much nobler house than House “Rented” Paid Links. It was against cheating clients and did their best to optimize sites well.
#3 Automatic Link Purchase and Generation
Just imagine: You don’t need to create content, optimize on-page factors, or make your site mobile- and user-friendly; your only goal is to automatically generate or buy links from third-party services. More links, higher SERPs.
Many SEO professionals understood that automatic links were no good, but, nonetheless, kept buying and generating them en masse, using such services as Rookie, SEO Hammer, and WebEffector.
#4 Link Spamming via Bookmark Services
To remember this method, you might be old enough to remember the times of “old” sites. By “old” sites, I mean sites that weren’t convenient to use.
Social links were as valued as regular, organic links. You could easily build dozens of backlinks by sharing content from your site and blog and it didn’t take much time at all. All you had to do was rely on such tools as Digg, StumbleUpon, Delicious, and URL.org for mass sharing.
These sites are social bookmarking services. Users used them to keep, share, and discover content. The services themselves weren’t cheesy, but SEO professionals harnessed them to trick the system.
Because social links had similar link juice to organic links, SEOs felt free to abuse bookmarks and spam social networks with links. Surely, Google had to act quickly to put an end to this easy-cheesy link building method that flooded each and every social network with junk bookmarks.
#5 Creation of Microsites, Satellites, PBNs
Links are still essential to the progress and growth of any website. Years ago, the situation was even worse, though: Link quality mattered more than link quantity, but it wasn’t obvious.
SEOs quickly came to the conclusion that: If links are so important, why should I rely on link farms that sell low-quality, junk links? I can build and drive links on my own. All I need is to create a network of microsites and satellites that pass their link juice to my home site.
Google’s penalty is inevitable if any factor (flagged IPs, penalized domains, similar anchor texts, thin content) suggests that your site has anything to do with this forbidden technique.
Indeed, many SEO practices of the past are forbidden now. However, if you look at it from a different perspective, you paid for what you got. The more you paid for links, the higher ranking position you came away within search results.
Today, it is quite another story. We don’t definitively know how Google works, and search algorithms are so smart that you have to play by their rules. SEO has become much more complex than it used to be. It has evolved into search engine marketing (SEM), but that isn’t a bad thing. It makes us strategize and adjust to the new realities of search.
Courtesy of SerachEngineJournal