Regarding (Slack/4)... I believe that toomuchtodo is talking about the following features within Slack:
* Stars: the ability to privately star individual messages (so you can easily find them again)
* Pinning: the ability to publicly highlight specific messages within a channel, much like pinned posts in a forum (effectively channel-wide starring)
* History links: click on the timestamp next to any Slack message and it'll open a canonical URL for that message, allowing you to drop these links to specific messages or points in a conversation into other chats, GH issues or anywhere else you fancy.
* Stars: the ability to privately star individual messages (so you can easily find them again)
* Pinning: the ability to publicly highlight specific messages within a channel, much like pinned posts in a forum (effectively channel-wide starring)
* History links: click on the timestamp next to any Slack message and it'll open a canonical URL for that message, allowing you to drop these links to specific messages or points in a conversation into other chats, GH issues or anywhere else you fancy.