The idea of Vouch is that people create a list of webmention senders they trust and make this available to others. If a domain is in a published trusted list then it has been "vouched for" meaning it's safe to accept and approve webmentions from that domain.
As David says "This should block automated spam and aid in moderation."
But, problem is, "(w)here do you find people who have been approved by people you have approved of?" How do we build lists and share them? Can a blogroll be such a list?
Various ideas were proposed including using a
rel value such as follower, following or contact, or maybe using microformats markup to declare
u-follow-of entries in a h-feed.
Now, the issue with a blogroll is that, unless it's explicitly curated, its member sites may well not be configured to send webmentions and it might be a bit of a waste.
As such, I thought my /Directory could be an ideal place to hold such a list. It is automated, only includes sites that have sent webmentions and only shows those that I approve - I've not had webmention spam but any would be removed from comments and not appear in the directory.
I've laid the groundwork by adding a h-feed and
u-follow-of markup to the Directory plugin (subject to tweaking but it's a start) so we now need the missing link of telling other sites where your list is.