I've updated to dev-libs/openssl-1.0.0a today, and it tells me:

Old versions of installed libraries were detected on your system.
In order to avoid breaking packages that depend on these old libs,
the libraries are not being removed. You need to run revdep-rebuild
in order to remove these old dependencies. If you do not have this
helper program, simply emerge the 'gentoolkit' package.

# revdep-rebuild --library libcrypto.so.0.9.8
# revdep-rebuild --library libssl.so.0.9.8

This won't work correctly for these three packages:

app-emulation/emul-linux-x86-baselibs
app-emulation/emul-linux-x86-gtklibs
app-emulation/vmware-workstation

because revdep-rebuild wants to emerge them repeatedly, since they're
binary packages. How do I report this? Do I file one bug per package,
or do I file only one for dev-libs/openssl where I list the three above
packages?