…in the eyes of Google.
If you've followed SEO or link building for any length of time, you will know that links are the currency of the web when it comes to helping boost a site's rankings.
However, Google change (improve?) their algorithms constantly in an effort to only show the best results to prevent Webmasters from using aggressive link building methods in order to game the Google search results (SERPs). Some of these efforts are more successful than others and there are still plenty of sites ranking well despite having used unscrupulous methods. All's fair in love and war, right?
But what about you? Let's say you own a site and you've decided to hand your link building over to someone else or you read somewhere that getting as many links as possible is a good thing? Let's imagine that you have bought some links. What's the difference between buying links and any other form of advertising? The short answer is it depends on whether the paid link is followed or not (more on that below). Most advertising platforms (think AdWords, Bing Ads – PPC), do not pass link value that can help improve your organic link value. However, a paid link that is followed does. So, whilst the intention may be honourable, the result isn't. Not, at least, for Google.
How can you check? Well, if you've really gone for it, you may well have received a message through your Google Webmaster Tools. If you're not using this, you should be!
You are looking for site-wide links from a single domain. If someone was going to link to you, it would be unusual for them to plant a link in a sidebar or footer and link from every page of your site (this is a popular ploy with web designers who think they are entitled to free advertising on your site).
If you have multiple links from a domain, how did they get there? Are they followed links? Did you pay for them or are they from one of those crappy scraper sites that plague the Internet?