Due to the efforts of a huge number of black-hat link builders, who engage in flagrant spamming and link buying, link building has a bit of a bad reputation. So much so, in fact, that it has given rise to Google setting up a whole web spam team headed by Matt Cutts.
Google just wants its users to have the most helpful and relevant user experience possible. But its hard line against link spam has seen the emergence of a nofollow link culture. Given the scale of the web spam problem something had to be done to try to safeguard the quality of search results.
But I think nofollow is contrary to the whole spirit of the internet - which is based upon connection, communication, collaboration and community.
Those who engage in web spam without giving anything back to the online communities they blight are failing in their SEO missions and ultimately wasting their time. Link spam still does yield some SEO benefits in many cases. But this seems likely to change as detection methods grow more sophisticated and the field of web spam detection evolves.
As for buying links, there is no doubt that it still works. But as long as your paid links exist you risk being caught and your site penalised. Google is also getting better at detecting and penalising paid links.
Blatant web spam is obvious to community members, who will ignore or even report it. It is also obvious to community moderators, who will remove it. If a community is poorly moderated it will be riddled with spam. links from sites infested with web spam are at best worthless and at worst damaging for SEO. With its dedicated webspam team Google certainly has the funding and expertise to fight web spam with increasing accuracy. And the longer web spam remains in place the more likely it is to be detected. So web spam is a risky, short-term strategy.
An important part of any effective online marketing is active, constructive participation in relevant online communities. Modern marketers should be looking to connect directly with their target audiences there. Not just with potential customers, but also with bloggers and website owners who may link to websites which have value for their own users. (By value I mean unique content that is relevant, useful, or compelling to the target users).
Most online communities have no problem with a profile link, perhaps even a signature link - provided the user contributes actively and constructively to the community. I see a trend away from banning dofollow links towards a policy of permitting valued community members reasonable and constructive use of links. I hope this trend continues.
A comprehensive SEO strategy should include valid, active participation in relevant communities. A large campaign may even require dedicated industry specialists whose job is to contribute valid content to communities and find people within the target audiences with questions that they can answer with their expertise.
This adds value to online communities and their other members. It also creates UGC (user generated content) for them. That has SEO and marketing benefits for online communities too. Quality relevant content means link attraction and keyword relevance. It also brings users in directly - for example users searching for an answer to the same problem will be drawn to (and likely revisit) the communities that provide them with answers.
Digital marketing strategy - and in turn SEO and link building - should be built around three cornerstones:
1) Identifying and empathising with the target audience(s), their needs and problems
2) Building compelling content and solutions that are tailored and relevant to those audiences
3) Constructive participation in online communities frequented by target audiences
Professional, constructive, white-hat link building in relevant online communities is meeting two strategically important digital marketing objectives:
1) Link building for SEO
2) Reaching out to customers directly.
If responsibly implemented it can also bring solutions, answers, and even SEO benefits to online communities. Everybody wins.