I am planning to add web 2.0 backlinks to my current backlinking strategy but I am confuse with something. The way I am planning to do it is spun articles submit it to web 2.0 and then blast the web 2.0 properties with blog comments. But this is were I am confused: I am seeing a lot of services that offers web 2.0 backlinks and they have tier 1, tier 2, tier 3. So can someone explain to me what is the difference of this in only using 1 tier web 2.0 then blast it with backlinks than using 1,2, or 3 tier web 2.0 properties. So 2 or 3 tier will be more effective?