My own personal view on this is that it makes perfect sense. Embedded chat widgets allow the bloggers who actually want to engage in a different kind of conversation with their readers to do this without compromising their privacy and without the risk of being flooded.
There are quite a lot of "communication models" available right now - Wiki for collaborative work, blogs for one-to-many broadcast, blog comments for many-to-one, classic IM for trusted one-on-one, etc.
Embedded chat define yet another type of communication model, sort of a casual non-trusted one-on-one. Just like with any other communication model, this makes sense to a subset of the people at any given time, and it's good to provide them with this.
I guess that for me the perfect chat widget would support masking my real IM, separating my online status in my real IM vs. the online status in the embedded chat, and some kind of "flood-control" - "allow up to 3 IM messages a day".
As for Yedda, we will offer IM integration in the cases where this makes sense, though I don't see us getting into creating a general purpose embedded chat widget - focusing on creating the best place for sharing knowledge is already more then enough for us
. I think that you will see us integrating this in the context of Q&A in some interesting ways in the near future...
And yes, ideas are worth a lot of money, but that's a topic for another potential startup
.