[Touche]

They do disappear off of your feed in which case you'll never see them again. There is no concept of "unread" tweets, like there is with RSS.

[nnkh]

You can scroll down. The latter is true.

[Touche]

> You can scroll down.

Not if you check it once a day (or even once an hour depending on how many things you follow), it's gone by then.