[buckket]

Yes, because there is no difference between an @reply and an ordinary tweet. Not technically at least. It’s just text. But implementing a filter on your side should be trivial if that’s what you want.

Maybe I’ll implement something which makes it easy for users to specify custom filters and/or highlights.

[JoshTriplett]

Given the decentralized nature, it'd be nice to parse any @reply , add metadata that indicates the full URL, and thus translate into a local user's nicknames.

[plomlompom]

Should be easy to add metadata by convention inside the messages, appended to them following some kind of control string, like "META". Clients could interpret anything from that string on by rules yet to be defined.