Granted, selling the software outright would be conveying, but what if the company leases their service on a remotely administered box colocated in a local data center? I think it is not totally clear that software has been conveyed, especially if it is under GPL2.
Regarding selling rights: you perhaps misinterpreted the scenario I am proposing. I am supposing that a company has written a proprietary "cloud" internet application that incorporates Zed's GPLed Lamson component -- which you say they can do because no software is conveyed. However, if they want to sell their software or (potentially) their company, I am saying that -- cloud or not -- they will be interested in acquiring a non-GPL license from Zed because the sale of their non-GPL software without such a license may run afoul of the GPL... which is why Zed's use of the GPL is relevant even in a "cloud" context.
Regarding selling rights: you perhaps misinterpreted the scenario I am proposing. I am supposing that a company has written a proprietary "cloud" internet application that incorporates Zed's GPLed Lamson component -- which you say they can do because no software is conveyed. However, if they want to sell their software or (potentially) their company, I am saying that -- cloud or not -- they will be interested in acquiring a non-GPL license from Zed because the sale of their non-GPL software without such a license may run afoul of the GPL... which is why Zed's use of the GPL is relevant even in a "cloud" context.