These are expressions that relate to links between websites, whether they are linking to your site from an external site, or relating to a link within your site going to a third party. For instance, you may want to link to a client, or a supplier may want to link to you.
The ‘follow’ status is used by indexing ‘bots’ (Google mini-programs that ‘spider’ the internet looking for links between sites) as an indication of whether any ‘kudos’ form the link should be shared from the source to the target. For instance a ‘do-follow’ link from a renowned site can be beneficial in terms of the way your site is viewed by a search engine. In most cases, links are ‘no-follow’ because Google regards the overuse of ‘do-follow’ links as generally a negative indication possibly flagging up a ‘link-farm’ trying to ‘game’ the indexing process.
A few years back, it was common practice to build up links by ‘buying’ posts with embedded ‘anchor links’ from bloggers willing to participate in such schemes. Eventually Google caught up with this process and virtually pulled the plug by penalising sites which it considered had used these tactics. In most cases, it was third party ‘SEO’ companies who generated these links in the first place. The result is that many sites are reluctant to provide ‘do follow’ links and by default provide ‘no-follow’ – This achieved using a bit of HTML code called a tag which looks like this: rel=’nofollow’.
It is important to note that a real visitor to a site with a link (as opposed to a ‘bot’) may click on the link and will end up at the target – so in terms of getting visitors to your site, having any type of links are important – however a ‘no follow’ will not help in terms of SEO. As someone who firmly believes in organic SEO, I am not so concerned about whether a link is ‘no-follow’ because I am more concerned with building links that will drive targeted traffic to a site.