As you probably know, the curation rewards of upvotes made within the first 30 minutes of a post are paid, in part, to the author of the post instead of the curator. The later you upvote a post within the first 30 minute timeframe, the higher your potential curation reward. The reason for this rule is to prevent curation bots to instantly upvote all posts from popular authors.
This 30-minute rule will be changed in the next hard fork, HF 20.
Steem development
Steem is an open source project and the development of the source code can be followed and seen on Github.
I've noticed two changes made by Steemit developer @vandeberg yesterday:
1. The curation reverse auction time will be changed from 30 minutes to 15 minutes.
According to most witnesses the 30 minute reverse auction time is too long and users are losing curation rewards without realizing the rule exists. This 30-minute time window will be reduced to 15 minutes. Here is the commit on Github: https://github.com/steemit/steem/commit/e45d5932a7ac76fd099219a3f8da6eedf240b3b5
2. The lost curation rewards from the reverse auction will no longer be given to the author, but go back into the rewards pool.
I think this change is a smart improvement, because it makes self voting less attractive. There is currently no penalty for voting on your own posts instantly, because the lost curation rewards get paid to you as the author of the post. After hardfork 20, when this change goes into effect, instantly voting on your own posts returns 25% of the vote value back into the rewards pool. Here is the commit on Github: https://github.com/steemit/steem/commit/d1fb4aebe6f0d141b87bcdddd9561abbe7b86d63
Both changes were proposed by the Steem witnesses. You can find a summary of some of the conversations regarding the proposal in this post on Github: https://github.com/steemit/steem/issues/1874.