[G_Morgan]

I think Mono is pretty patent clear (at least as patent clear as it gets). The worry is not what patents exist on the project, it's what they won't be able to implement in avoiding patents. Compatibility issues have killed more technologies that patent warfare ever will. The fear is that Mono could encourage greater acceptance of .NET in the short term while in the long term MS could kill it via extension. The last thing people invested in FOSS want is to promote a foreign technology that will undoubtedly be legally incompatible with FOSS in the future. The same issue applies to Silverlight IMHO (and I'm far more worried about Silverlight than any other part of the .NET stack).

My perspective on it is that Mono is fine if you want to use only FOSS technologies. Avoid stuff that is from MS and isn't in the ECMA standard and it's no worse and probably better than anything else in terms of patent threats. For example Gtk# is FOSS technology, there's no way MS can claim patents on that without threatening the rest of Gtk+. In that case no language is safe. It's why I'm not too concerned with Gnome having an increased Mono presence because all that stuff is using the Gnome API. It's not as if people are writing Linux applications using Winforms and ADO.NET and there is absolutely no legal threat from MS over the ECMA standardised parts.

Of course this means it is not a Java replacement. You can safely (as it gets) use the Java API on Linux, Windows or the Moon if you want. Of course none of this changes the fact that Swing is quite painfully slow to render. Not as bad as it used to be but there wouldn't be a javaGTK, javaQT, SWT and so on if people were happy with Swing. Of course if people separated their GUI's from their application logic it wouldn't matter too much since they could move from toolkit to toolkit at will.