Ok I regularly post new quality content to my e-commerce site but I am now starting a tiered link building campaign to boost back links and rankings. I have created some Tier 1 web2.0's on Wordpress, Tumblr, webs.com. these include a few 500 word articles each, videos/ images/ contact page/ about us page etc. I will link out to relevant authority websites and also will add link to my e-commerce store. Was going to wait a week before adding my link to make it look natural, is this necessary? Shall I post links to these web2.0's on social bookmarking sites? What shall I do for my tier 2? write articles linking to tier 1? Was thinking of buying GSA SER or should I just purchase things like blog comments and backlinks for tier 2 and 3 from fiverr? Is GSA easy to use? Any help would be appreciated..