There are lots of plugins for blogs built on WordPress that perform various functions. Don't be in q hurry to Install just any one one your blog. one reason why that is so is that too many plugins on your blog can make your page take much time to open - based on experience and research. I always read plugin functions first before installing it and so should you. Among the common plugins recommended to install are the WP Spam shield, Google Analytics and the Jetpack BT WP. See full details here http://newbieblogging.com/useful-plugins-for-wp-blog/