Why no points when voting for best answer?

You DO get a point for each vote you cast.

Perhaps you are mistaking the "thumbs up" icon as a vote??

That's just an opinion you are giving---not a vote---and you get no points for that.

When a question is "closed" for any further answers----a blue tab appears under each answer where you can choose which one you want to vote for.

Points and Levels

To encourage participation and reward great answers, Yahoo! Answers has a system of points and levels. The number of points you get depends on the specific action you take. The points table below summarizes the point values for different actions. While you can't use points to buy or redeem anything, they do allow everyone to recognize how active and helpful you've been. (And they give you another excuse to brag to your friends.)

Points Table

Action Points

Begin participating on Yahoo! Answers One Time: 100

Ask a question -5

Choose a best answer for your question 3

No Best Answer was selected by voters on your question Points Returned: 5

Answer a question 2

Deleting an answer -2

Log in to Yahoo! Answers Once daily: 1

Vote for a best answer 1

Vote for No best answer 0

Have your answer selected as the best answer 10

Receive a "thumbs-up" rating on a best answer that you wrote (up to 50 thumbs-up are counted) 1 per "thumbs-up"

Levels

Levels are another way to keep track of how active you (and others) have been. The more points you accumulate, the higher your level. Yahoo! Answers recognizes your level achievements with our special brand of thank you's!

And finally, as you attain higher levels, you'll also be able to contribute more to Yahoo! Answers - you can ask, answer, vote and rate more frequently.

Level Points Questions Answers Comments Stars Ratings Votes

7 25,000+ * unlimited * 100 unlimited 100

6 10,000 - 24,999 * unlimited * 100 unlimited 100

5 5,000 - 9,999 * unlimited * 100 unlimited 80

4 2,500 - 4,999 20 80 40 100 unlimited 80

3 1,000 - 2,499 15 60 30 100 unlimited 60

2 250 - 999 10 40 20 100 unlimited 40

1 1 - 249 5 20 10 10 0 20

*All limitations are per day

Go into your profile and click the activity detail tab and it will show you getting points for voting. They only show you a little bit of detail, so go in a vote some and then check your profile. Now if you vote "No best answer" then you don't get points for them.