According to a post on an news site dedicated to news about the distribution, the decision was taken at the recent Ubuntu developers' summit.
The next version of Ubuntu, 10.10, named Maverick Meerkat is due to release in October this year. Shotwell runs on Linux and Windows, the latter with limited features.
Mono, an attempt by GNOME co-founder Miguel de Icaza, to develop an open source implementation of Microsoft's .NET development environment, has been included in Ubuntu as a default for some time due to F-Spot and a note-taking application, Tomboy, being default apps.
In its recent release, 10.04, Ubuntu also has a game named gbrainy which is dependent on Mono.
The Fedora GNU/Linux distribution, which is a community effort supported by Red Hat, jettisoned Mono sometime back and now uses Gnote as its note-taking application.
GNU/Linux distributions which offer KDE as the default desktop environment have long had a top-class note-taking application in Basket.
Comment has been sought from Canonical on the reasons behind the decision to get rid of F-spot.