The matter is all a bit confusing, but from what I understand now, Josselin Mouette has made Tomboy a dependency for GNOME on Debian Squeeze, which means that Mono is now part of GNOME for Debian Squeeze as well. This seems rather odd, because Debian never seemed to be too keen on including Mono.
The news got out via a blog post by Debian maintainer Robert Millan, who maintains the Gnote package for Debian - Gnote is a non-Mono replacement for Tomboy written in C++. He writes that he is not particularly happy with this move, because he believes that a note taking application shouldn't be part of the default selection anyway, especially not one which drags 50MB of dependencies onto the first CD.
What makes this story so confusing is that Josselin Mouette points to bug #532355 as rationale for the inclusion of Tomboy. This bug advocates Gnote as an alternative for Tomboy; Tomboy was, up until now, a "recommended", but optional, package. Gnote was promoted as an alternative since Tomboy's architecture support is limited, a problem Gnote doesn't have.
And here comes what confuses me: Mouette claims that because we have Gnote now as an alternative to Tomboy, Tomboy can become a dependency because Gnote can come into play on architectures Mono doesn't support. In addition, Gnote can serve as an alternative for people who don't want Tomboy because of the 50MB issue. Which makes me wonder: why not just go for Gnote altogether?
I'm sure this won't be the last time we hear of this.
Indeed, this wasn't the last we heard from this. Fedora Project leader Paul W. Frields expressed his concern over Mono. "We do have some serious concerns about Mono and we'll continue to look at it with our legal counsel to see what if any steps are needed on our part," Frields said. It could be the case that Mono will be excluded from the repositories for Fedora 12. The reason for this is that Gnote will replace Tomboy in Fedora 12.