A few days ago, at the recommendation of @cgutteridge, I changed the default FOAF class from foaf:Person to foaf:Agent, when representing Twitter users.
As Christoper rightly pointed out, foaf:Person is used specifically to represent real-live people, whereas many of the accounts on twitter are either organisations or bots of various kinds. As such, foaf:Agent is the [...]

programmableweb.com has just listed semantictweet in their catalog of mashups.  They have also tweeted about it.
Cool!
I’ve submitted the story to digg, so if you like it, please digg it!