Develop a "Likes" link

Nothing out of the box. You may be able to repurpose the Ratings control and whenever someone "Likes" a comment, just default the rating of that comment to 1.

Other option would be to create a custom form control or a webpart that works with the comments and when a comment is liked then store a counter or a record in a table with the comment ID and total.

I think there are several ways to skin this cat, just pick your poison. :)

Thanks for your answer. Since I am new to Kentico, I kinda need to stick to what I already know for now.

What I want to do is add the "likes" button through the transformation and every time that it is clicked then call a WebService passing the UserID and the DocumentID of the blog just liked. The method would insert into the database.

My question is how do I create a webservice in kentico. In the real world I would just create a webservice application in Visual Studio and add a reference in my project. Is there a KB that has information about creating a webservice. I found one reference, but its pretty old (version 5) and I don't know whether I can add my own methods or not.

Thanks.