Firstly coinurl.com is a link shortening service, which will create a shortened link that will display an advert first then take you to the destination page. So by doing this it is yet another way to grow your BitCoins. Advertisers will pay coinurl to show there websites and whoever creates a shortened link you will receive a small number of satoshis for any successful click through.
So this is yet another way to grow your coins. If you have a blog or a website you may want to consider using coinurl! Especially if you have a lot of traffic coming through your site.

Also you may want to consider buying some advertising from them to gain more traffic to you site!