how many of you block webarchive through htaccess or robots.txt?

[MWpro]

Is this generally a good idea, so that no one can have any proof of things that were on your websites years ago?

What is the preferable method for blocking?

[phranque]

the preferred method for preventing content archiving by well-behaved bots is the noarchive robots meta tag.
a couple of recent WebmasterWorld threads have some useful information in that regard:
[webmasterworld.com...]
[webmasterworld.com...]
the reason you might use this is time-sensitive content.
there may also be IP related reasons for not allowing archive.
you can't actually prevent someone from archiving content once they have gotten it.