Using Google Alerts is a good way to find websites and blogs who are talking about your site or topics that are related to topics you are writing.
Google Alerts sends you links in your email at regular frequency on related links. This way you can find those webpages and visit them in order to ask them for a link back or write a comment on their blog etc.
This method of link building helps you generate lots of related similar themed links and increase your SEO and Organic link popularity.
Google Alerts also helps you know sites which are negatively talking about your site and sites which are positively talking about you. It also helps in identifying backlinks to your blog.
