URL Bob is a completely free tool where you can create short links. These short links are useful when you want to share your long urls into social media sites like twitter. For better user experience you can select no ads (advertisement) during creation of short links at urlbob.com.
During creation of short link at urlbob.com, you can select ads (e.g. Banner ads) option, and earn money by sharing your short link. When user click on your short link, user will be travelled through advertisements to reach fiinal destination link. This is how we earn from our advertiser and then we will pay you for each short link clicked by your visitor.