Getting, and keeping, visibility of ones online reputation is essential in managing it effectively. Reviews, comments, news stories, articles, posts, and more are all time sensitive. Here's some tips to being, and staying, aware...
Grandaddy of Monitoring
Google Alerts - it's the most popular way to know when something is said online.
For LinkedIn and Twitter
LinkedIn Signal - a nice way to monitor mentions on LinkedIn and Twitter
Watches 100+ networks
Social Mention - keeps an eye on almost every social network