Here are some great plugins that will help bookmarking with social networks easier and more beneficial to you.
Step2
Share This - This plugin will allow your visitors to share your content via social bookmarking sites and/or e-mailing the post to a friend. Plugin supports the Share Icon project. You can see it in action on my blog. An awesome plugin that don’t take much space on your blog and yet proved to be invaluable source of traffic for me.
Step3
Ultimate Tag Warrior - Ultimate Tag Warrior is a multi-headed hydra of a plugin. It allows you to add tags either through the Write Post page in WordPress in a tag box, on posts using an AJAXy box, and in posts using special syntax from external editors (or internally, if you’d like). From the write post page, you can also get suggestions for tags using the Yahoo! Keyword suggestion service.
Step4
Tagalize It - Create tagged text by enclosing the text to be tagged in one of the following. [TAG-Tec] [Tag-Ice] and [Tag-self] also alternate tags can be inserted into the [Tag-tec “new tag”] By Todd Sieland-Peterson. Works flawlessly with UTW and makes creating tags within your post a breeze.
Step5
WP-Email - Allows people to recommend/send your WordPress blog’s post/page to a friend. I personally like the option to add icons that people are so used to for sharing your posts. Install according to author’s instructions.