Dave said Straw competes with his own software. I never really thought about it that way, but I can see his point of view. Two things about their relationship and the competition.
I've never used Radio, but it is a full-blown weblogging tool, for both authoring and aggregating content. Straw is strictly an aggregator. I have no idea what percentage of UserLand's Radio customers use it only for aggregation, and I don't expect them to tell, but still, the focus is different. I've been thinking about writing a desktop weblog authoring tool, with possibly some kind of communication going on between it and Straw, but that's a project that might never happen, and would be a separate tool.
The other thing is platforms. Straw is written for the GNOME desktop. Radio works on Mac and Windows. I don't have access to those platforms, and therefore Radio; users of those platforms don't (well, I suppose OS X users might theoretically run Straw) have access to Straw. GNOME does — or will some day — compete with those two desktops, and I see Straw as a part of that, and in a way, Radio is on the other side of that fence, as a part of the larger world of those two desktops. But that's desktop A versus desktop B, not software package Z running on A versus software package X running on B. But unlike me, Dave has a commercial interest in this, so I wouldn't be surprised if he saw things differently.
Of course, Radio might be ported some day, and so might Straw (no, that's not in the current plans and I have no interest in doing it.) If they do port Radio, I genuinely wish UserLand the best of luck with it, because I'd love to see them, and a commercial desktop software package for "normal" users running Linux, succeed. I don't know if the time is ripe yet.