What is link begging?

To asked someone to submit you site link  to their sites.

Link begging is a way of alerting people to your content. Especially if you're just starting to build links for a relatively new blog or website, this can be a valuable way to get the word out about what you're producing. It makes sense: If people don't know the resource you're offering exists, their chances of linking to it are zero. In the early stages of your business, link begging can be an aspect of PR and brand building.