Instead of using the old "RT" (or "via") approach (both of which having nothing to do with core Twitter actually - they grew organically from what users wanted) Twitter have added a "Retweet" button on the web (and all Twitter clients will be in a mad rush to catch up).

Personally I love the facility and I can very much see how this can be useful (think of the ability to accurately track the viral impact of content etc) but the one thing that nagged me was that you could no longer add a comment to the end. This seemed like a bit of a downer as I think it really can add value.

So I'm glad to see, in an excellent article by Twitter founder Evan Williams, that Twitter are very much aware of the issue:

The other thing some people will not like is that, unlike organic RTs, there's no way to annotate or leave your own comment when you retweet something with the new system. Some people annotate with every retweet, some don't do it at all. But it's definitely useful in certain scenarios. We left it out of this first version mostly for simplicity. It's especially tricky when you consider transports like SMS where adding a lot of structure or additional content is hard. But we have some ideas there, and it's possible we'll build that in at a later date. (This point should not be missed.) 

This makes me very happy!