Link building is the practice of creating one-way hyperlinks (also known as “backlinks”) to a website in order to improve search engine visibility. Common link building strategies include content marketing, building useful tools, email outreach, broken link building, and public relations. Most link building agencies focused on outreach charge a flat fee for each link they create. It's good to know what NO LONGER works, but it's even more painful to know the high cost of what works.
Link building is 100% a necessary part of a solid SEO strategy. In addition to making search engines so proud of your content that they rank it well, your users will also be happier. When a visitor comes to your site via a backlink from another location, it's a recommendation. The other site has attested to you.
Because of all of this, Google and its audience will see your site as an authority. This method of link building can generate benefits, such as referral traffic, or help position you as a thought leader. When you add links yourself, you usually have full control of the outcome of the tactics, rather than relying on a journalist or other third party to link to your site. I'll say this, I'm not very fond of sculpting page ranges, but internal links are a huge missed opportunity for law firm websites, for whatever reason, whether it's the marketing people or the places that are building these sites, you don't think much about the internal linking structure and it makes huge difference.
While link building seems to require more effort than most SEO strategies, in the end it will be rewarding and will last in the long run. Personally, I don't recommend building black hat links (the risk doesn't come close to justifying the reward). But Google has improved a lot in understanding links and one of the things it does read is the link text. Any link intended to manipulate PageRank or a site's ranking in Google search results can be considered part of a linking scheme and a violation of Google's Webmaster Guidelines.
It depends on who you are and what you specifically need, but a link building service, at least one that is legitimate, can save you hundreds of hours of work for an incredibly long-lasting boost in the SERPs. Google says it's a clue, but people building links have been interpreted as saying that no-follow links have no value, don't affect page ranking, it doesn't matter, blah blah blah. Natural links are produced more organically from readers who come across your website, including a link on your blog or website without being asked. Nofollow links are commonly used when you want to create a link to another website, but you don't want to tell Google to crawl that site.
Nowadays, you don't have to worry so much if you have unwanted backlinks pointing to your site, as long as you haven't participated in a link building scheme. To gain a true competitive advantage through links, you need to adopt a strategy that allows you to get editorially placed links.