Andrew Black and I have been working on extending the OB in various ways 
to best support Traits, and I just thought I'd report that the OB has 
been very productive as a framework for these extensions. Some kinds of 
extensions we've done with pretty amazing ease, and no deep changes to 
the OB:
1. Add computed method categories
2. Show more complicated hierarchies instead of just inheritance 
hierarchy in the class column.
3. Used colors in the class name column to distinguish Traits from Classes.

Adding menu items and such in a way that's dependent on the precise 
object selected should be more trivial than most of these, but we 
haven't done this yet.

Some of the tools in OB itself are great (the senders/implementors 
chasing is very nice), though we did occasionally miss some menu items 
present from other browsers. Actually, we mostly missed the RB stuff, 
which from looking at Squeak Map, can be incorporated via Services...

Ok, gotta go. In short, if you're contemplating browser extensions, my 
advice is to invest the few hours required to delve the depths of the 
OB. A few docs on the wiresong Wiki give a general idea, but mostly it 
takes some digging. But once you've learned how to make it work for you, 
it does a LOT.

Daniel