I want to thank John for creating a PortableApp for PuTTY!
When I donated money to PortableApps (which I encourage all users of this wonderful service to do), John emailed me back personally. He thanked me for my donation, and asked if there was any particular improvement or app I would like to see. My only request was a Portable version of PuTTY.
Writing security code is difficult, and previous attempts to make PuTTY portable (in particular, portaPuTTY) modify the source. This makes me nervous, as I am not a programmer and I worry about what else may be modified.
PortableApps work differently, by wrapping the executable and running code before and after the main executable. By not modifying the source, the responsibility for security remains in the hands of the author(s), where it belongs.