A kudo is a compliment or a 'good vote'. If you like a thread you can click the little thumbs-up sign in the left upper corner to give it a kudo. The number of kudo's a thread has been given will show up next to that sign and in the list of threads on the forum index page.
Ths is what Yuku has to say about kudo's:
You can give kudos on profiles and on posts. Kudos -also called good votes- can be given when you like a profile or a post. You must be logged in to your yuku account in order to give kudos.
Kudos on posts.
To give kudos on posts, click on the blue thumbs-up image above the lead post.
Your kudo will automatically be added.
You can only give one kudo per post. After you have given a kudo the colour of the thumbs-up image will change from blue to grey.
To find out who else has given kudos to the post click on the kudos link.
Kudos on profiles
To give a kudo on a profile, click on the kudos link under the avatar.
Should you wish, you can leave a comment after giving a kudo.
You can only give one kudo on each profile.
Viewing who has given kudos on a profile
To view who has given kudos on a profile, click on the kudos number under the avatar.
On the next page you can find out who has given kudos on that profile, whom the owner of the profile has given kudos to and the progress of the profile in the Kudos Hall Of Fame.
To find out more about the Kudos Hall of Fame, visit our Hall of Fame tutorial (coming soon)