The page I linked to was mostly intended as a nice example of Webmentions being used in the wild, but I also thought it made a nice point about the risks of cen

The page I linked to was mostly intended as a nice example of Webmentions being used in the wild, but I also thought it made a nice point about the risks of centralized systems versus decentralized ones. Examples of the latter would be spam (as mentioned elsewhere above), and coordination problems when trying to upgrade the standard in potentially backwards-incompatible ways. Hopefully the continued adoption of Webmention will prove that these risks are manageable.