Question about bookmarking

Hi

Thanks for anyone that has answered any of the questions I have posted on here, I know a little bit about off page seo and my sites are doing fairly well but I want them to do better and want to make sure that when I decide to start implementing a new stratergy that it is done to the best of its ability.

My question is about bookmarking:

I see people saying to make loads of accounts and keep bookmarking yourself, this is not something I am going to do.

What I was thinking of is signing up to all the bookmarking sites that are do follow and adding my sites and anything else I do towards my sites such as profiles and articles and other stuff that I do on other sites about my site.

I have 2 questions, firstlyn is it ok to sign up to all the bookmarking sites with the same username, there or there abouts the same?

Secondly if I am only bookmarking my sites and stuff on other peoples sites that are about my sites is that not a good thing to do? Do I need to add other sites as well?

Thats all for now, any other good advice people have about bookmarking sites would also my greatly appriciated.

Thanks

Mark