I have 20 sites as addon domain.I create backlinks for all sites by blog commenting in same page.I saw that some site get good results some are not.If I create blackinks for all my addon domain will all of them get same linkjuice or only one or two get linkjucie as all my addon domains from same IP?
all of them will get the juice of each link, yes addon domains are on the same ip but you have to optimise each individual subdomain as a totally seperate website. Google knows about the ip address and understand more than one site will be on it, so you have to optimise that individually
No matter how many sites are added on, if they are properly optimized, they will get link juice accordingly.
You can only optimize all addon domains individually! for transferring the better juice which you are expecting & make sure to choose blog commenting in concern topics to find more edge
It certainly helps with gaining site authority. It is even better for your url home page if you build the links for sub-pages and sub-domains.