Hi there Sukesh,
--First thing first, ask for "blog reviews' in the "review" section :)--Check out the topics "Beginner's guide for new members" and "Welcome! Please read this if it's your first time"first section in the forum, they contain all basic guidelines one needs to follow.
ans.1 Via participation :) participate in forums, chats, contests. Submit your blog posts on indivine, which is specifically created to share.
ans.2 adding someone in your circle needs no confirmation, you will be able to see that person's blog posts on your network. its like a customized list. if the person adds you back, then you guys can share indimail (ie. indiblogger emails) too.
ans.3 If by useful you mean for blog and bloggers then its very useful. I have been to my first indimeet and its been very nice. Not only did i get to interarct with senior/peer/junior bloggers but also got to know many experiences,tips, tricks and it all. Obviously, had lots of fun too.
ans.4 i have seen you replies on Inditalk, Inditalk is the common platform for eveyone to chat. otherwise its indimails
Meow :)
:D Thanks.