I am currently refurbishing a lot of outdated specfiles, and I remember talking about soft dependencies, which would come in handy for a current specfile (i.e. lighttpd suggesting the most popular modules to be installed, like mod_rewrite, mod_redirect).
My main issue is, google seems to fail to release any bit of valuable information on the implementation status of the Suggests: statement, its current overall status and rpm version requirements. Most documents and howtos are from 2004 and earlier, too outdated to be considered a trustable source. The absolute rpm pdf does not state anything about the Suggests: tag either.
Thanks a lot for any information in advance.
Post scriptum: OpenSuSE & Mageia seem to use it, but beyond that..
https://build.opensuse.org/package/view_file?file=meld.spec&package=meld&project=openSUSE%3AFactory
A message on a mailing list indicates rpm 4.4.3 introduced it
http://www.redhat.com/archives/rpm-list/2006-January/msg00034.html