> because some apps (like, for example xine) doesn't like it, when some of their
> dependencies get upgraded with a --deep world (like ffmpeg or transcode),
> while themselves are not recombiled.
>
> xine will not crash - but some video-filters will be gone.


Whoa. Now I know why my mplayer cannot read mpgs anymore. Thank you guys. Anyway, I recompiled it a couple of days ago with a bunch of new use flags, so I hope it will be fixed now.

But it was the only problem I ever had with emerge -Du world. If I can have a new lib that will fix bugs or improve something, I want it. I won't bother recompiling some app that will complain, if needed. But of course I'm talking of my desktop system, I think I would have a very different approach for a production system.