What do you mean by auto social bookmarking plugin Are you looking for this one ? http://www.dountsis.com/projects/social-bookmarks DON.
Im talking about something which after every post bookmarks the post as a new bookmark on the social bookmarking websites
I know a few of the social bookmarking sites out there will give you a light smack if they notice that the only thing your bookmarking is your site and every single post you make. I mean if you don't care or don't think you'll get caught / etc.. no biggy have at it. If you do though I'd be weary about an auto submitter OnlyWire Autsubmitter: http://www.lionstarr.de/onlywire-autosubmit-a-wordpress-plugin.html might be something along the lines of what your looking for? I haven't actually used it so I'd research it first to see if that's what your looking for.
if you use auto bookmarking, use a trusted account. it's true, as pointed out earlier by one of the posters, that your account can be flagged down if the site owner notices that you're submitting just one site. you must submit other sites too. gain trust first. you can proceed later. why won't you go for manual submission? it's the safest and enduring method.
you can put something like the 'add to any' plugin at the end of each post and then go in and manually submit articles you feel are worthy.