All good SEO consultants know for a site to do well for competitive SERPs that page/site needs links (as many as possible please :-)). Some sites have no problems gaining text links naturally, but many small businesses struggle to compete for Google SERPs due to a lack of quality links.
And so purchasing text links has sprouted a thriving niche SEO industry which has it’s own set of pitfalls.
Buying text links is a touchy subject in the SEO community. The white hat SEO consultants think it’s a blackhat SEO technique and so frown on it’s use and the blackhat SEO’s know if done correctly buying text links can help a sites performance long term.