Long term rewards can be done via tips.  Any individual vote has almost no ability to pay someone unless it works with many other users.  This means that with the exception of a few whales, the long-term payouts would only apply to content that goes viral on steemit after more than a week delay.  Possible, but unlikely.

if the technical stability is greatly affected then balancing the two (stability and a more streamlined reward approach) , 7 days would make more sense then 24h.
Still, some categories of  users fall out of the employee range and fit into a more continual reward expectation: writers, musicians etc. and we might need to respond to their needs too.

On the downside, Trending posts algorithms need to be well thought and will bring their own downsides and benefits.

_Edited to remove the 30 days reference which is proposed to be removed._

Don't all `comment_objects` need to exist in memory (at least with minimal data of author and permlink) anyway? The blockchain needs to check whether a post operation has a unique author/permlink so that it knows whether it is creating a new post/comment with a payout period, or just doing an edit.

So, we are talking about keeping maybe a couple more fields in `comment_objects` for validating nodes. And if you compare that to the amount of memory full nodes need to keep (whether the post is archived or not), that additional memory overhead is very small. 

Memory access patterns for validating nodes are more of a concern, but I doubt most old posts will continue to remain active. And isn't this one of the advantages the ChainBase upgrade provided? That the database can support a much larger amount of infrequently accessed memory (since they remain on disk rather than in R AM)?

Also, I supposed it doesn't have to be indefinite. But archiving a post/comment after just 1 week is really short. (By the way, does archiving a post/comment mean that no new child comments are allowed? Because otherwise you still have the limited attention problem since   new comments with active payouts can exist nested in the discussion thread of a months old post.)  So what about up to 52 1-week long payout periods (which are only activated after the first payout if there is a new vote), and then a year after the post/comment was created, no new payout periods can be started?

how will the 7 day payout scheme affect the daily trending page?