Limit Posting Links has the exact features like its name. It helps administrator to limit the number of links inside a thread/post and to decide who could insert link inside the content.
This add-on could reduce spam, ads when only active members could post links.
Active member is someone who has posted, commented on the thread/site to post links. The administrator could decide how many posts for members to start posting links. This could help avoid some bad content which be abused by unhealthy purposes.