Disappearing online screenplays

Someone asked, following the recent post titled Screenplays: 'Tis the season..., Why do screenplays disappear from the internet? 

You, dear reader, can find the answer right here. 

I would have liked to read some of those, too. Never mind. The lesson, according to Robert Herrick, is: 

Gather ye rosebuds while ye may,
Old Time is still a-flying:
And this same flower that smiles to-day
To-morrow will be dying.

Or under legal threat. Or something...