Delayed Twitter hashtag streams
Following hashtags on Twitter is a great way to participate in real-time discussions of current events. But, what if you can't watch a playoff game or reality TV show until after it airs? There's nothing worse than knowing the outcome ahead of time. Right now, you have to choose whether to forgo reading Twitter reactions as you watch or to chance stumbling into a spoiler. But, this isn't a choice that people should be forced to make. Twitter should allow you to specify a time delay when following hashtag streams.
Twitter recently announced upcoming changes to the core timeline product. This seems like another easy way to (re-)engage users and make sure that they're being shown the most relevant content.
I looked into prototyping this feature using the streaming API, but unfortunately the end point is still in closed beta.