I created some web 2.0 properties for my money sites. Today I check them and I see 1 of them get pr 2 and 3 other web 2.0 get pr 1. Now my question is if I post some articles with 1 contextual link on those web 2.0 properties home page what will be the effort? Are these website help me to get more powerful backlink? Can you suggest me how I can use them? Because they are already got pr and I don't want to left them alone. Please suggest me.