Just have a look at this Screen-shot:

enter image description here

How come I get only +8 reputation for an up vote to an answer posted by me?

Here is the link to my reputation statistics page (from were this screenshot is taken):



You hit the reputation cap for the day.

You can only get 200 points from upvotes and suggested edits per day. Any reputation from votes after that point are lost. This also means that if you get a +2 from a suggested edit the final upvote will only give you +8 (192 + 8 = 200).

Reputation from acceptances and bounties are immune from this cap.

For a lot more information see the Meta Stack Overflow question:

How Does Reputation Work?

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