Have you tried doing them yourself? What happened to your ranking when you submitted a video to youtube or converted one of your blog post to pdf?But logically, as per research and analysis on micro-level, these methods are still working if doing with proper manners.
Guest blog posting can have value but 99.9% of them are pointless. The ones that do add value only accept material from trusted sources and are not easy to join.
Lets say you spend 10 hours on link building. At £10/hour in wages that's £100 for something that might or might not work. But spend £100 on PPC ads and you have instant success.
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