Gnus is quite fast when scoring the “traditional”
headers—‘From’, ‘Subject’ and so on. However, scoring
other headers requires writing a head scoring rule, which means
that Gnus has to request every single article from the back end to find
matches. This takes a long time in big groups.
You can inhibit this slow scoring on headers or body by setting the
variable gnus-inhibit-slow-scoring. If
gnus-inhibit-slow-scoring is regexp, slow scoring is inhibited if
the group matches the regexp. If it is t, slow scoring on it is
inhibited for all groups.
Now, there’s not much you can do about the slowness for news groups, but for
mail groups, you have greater control. In To From Newsgroups,
it’s explained in greater detail what this mechanism does, but here’s
a cookbook example for nnml on how to allow scoring on the
‘To’ and ‘Cc’ headers.
Put the following in your ~/.gnus.el file.
(setq gnus-extra-headers '(To Cc Newsgroups Keywords)
nnmail-extra-headers gnus-extra-headers)
Restart Gnus and rebuild your nnml overview files with the
M-x nnml-generate-nov-databases command. This will take a long
time if you have much mail.
Now you can score on ‘To’ and ‘Cc’ as “extra headers” like so: I e s p To RET <your name> RET.
See? Simple.