In the early 2000s, buying and selling paid links to increase rankings in the SERPs was a common occurrence in the world of SEO. It was an acceptable SEO link building practice until 2007, when Google declared that paid links were in violation of their Webmaster Guidelines , as they were purposefully trying to manipulate the search results. As Google stated,
…some SEOs and webmasters engage in the practice of buying and selling links that pass PageRank, disregarding the quality of the links, the sources, and the long-term impact it will have on their sites. Buying or selling links that pass PageRank is in violation of Google's Webmaster Guidelines and can negatively impact a site's ranking in search results.
If there is anything that I have learned in my 12+ years as an SEO professional, it’s that when Google decides something is black hat, they mean it. Plenty of SEO firms had to revamp client strategies when the news broke in order to keep their sites on the right side of Google’s line in the sand. Google did admit that not all paid links  directly violate their guidelines, such as links purchased for advertising, but that they work hard to discount other unnatural links  designed to cheat the system.
Flash forward to 2011: Are paid links (in some form) at all useful for your SEO?
Paid Link Type #1: Directory Links
I might be one of the few remaining SEO experts that consider directory submissions to still be a useful component of link building. Case in point, I launched a new page of content on my company’s site and wanted to do minimal link building to help it out. I submitted the page to two different directories and within one week it was on page two of Google. I’m not saying that the directories were the only contributing factor to the page’s success, but I think they definitely helped.
There are probably hundreds, if not thousands, of online directories you could submit your site to. Some are paid and some are free. Many will argue that paying for a directory submission is the same thing as a paid link, but I have to disagree. When it comes to directory submissions, the key is to stay small. Don’t submit your site to every paid directory you can find. Select a few relevant, aged directories that might actually help out your site!
Directory links should never make up the bulk of your link portfolio, but one or two links from quality directories helps diversify it that much more.
Paid Link Type #2: Online PR Links
I think links from press releases (sent out through paid PR distribution sites) are incredibly valuable for a number of reasons. Where companies run into trouble is when they are publishing three press releases a week. That’s essentially spam. Your company cannot possibly have enough newsworthy information to be writing that many press releases that frequently! You should limit your press releases to when your company actually has news to promote such as the launch of a new product or service, an event and so forth.
A newsworthy press release doesn’t just give you links, it can also help build awareness and buzz about your brand and increase your online presence. Those press releases have the ability to rank in the search engines, keeping your company ranking for unbranded search queries. If you are just writing and publishing online press releases for the links, you’re missing the bigger picture.
Paid Link Type #3: Paid Blog Reviews
Paid blog reviews are kind of like a double-edged sword. Just because you paid for the review, that doesn’t guarantee that you will like what someone writes about your company/product. On the other hand, paid blog reviews aren’t as trusted by your target audience as unpaid blog reviews because people assume that reviewers won’t be as critical. However, when used appropriately and effectively, paid blog reviews can have powerful effects on your SEO, especially if you are looking to generate buzz around a new product/service.
If you manage to get a paid blog review on a popular industry site, you are getting high-quality links. But that isn’t the only benefit. A popular industry site or respected blogger probably has a large (or at least dedicated) following. A good portion of that traffic could get passed along through that paid review and over to your site. A large amount of targeted traffic is never a bad thing!
Paid Link Type #4: Useless Anchor Text Link, aka “Sites We Like/Blogroll”
Google freely admits that “Buying and selling links is a normal part of the economy of the web when done for advertising purposes, and not for manipulation of search results.” Things like banner ads could be classified as paid links, but Google doesn’t see those as an attempt to trick the search algorithm. A banner ad is a marketing tactic in the same way a television ad is.
Banner ads, just like PPC ads, are a great way to build awareness and drive traffic through to your site. A banner ad on a related website positions your site in front of your target audience and creates another touch point to connect to them with.
However, purchasing links that are just anchor text fall soundly in the “manipulation” category. Have you ever come across a site with a directory page that was just full of random links? Chances are those were either paid links or some sort of real partnership. These are the kind of paid links Google warned site owners not to bother with.
So are paid links any help for SEO? Yes and no. If you are just looking to buy a link to help in your link building , it’s probably not worth the money. You could invest the cost of that paid link into branding your business online with content marketing or social media. A paid link is a good and useful marketing tool when it’s used to drive traffic, increase brand awareness and promote your website.