I can't even remember when this was mentioned. It might have been at BarCampSheffield or a event before that. But the news that someone was working on a web front end/web application for tomboy notes totally shook my world.
Snowy is a online service that syncs with Tomboy notes to allow complete access to your notes online. Its uses Django to create a REST API for Tomboy notes, so other applications beyond Snowy can take advantage of your notes too. This means you can easily create a web app for your mobile phone or other devices. Hell, you could consume your notes into yahoo pipes or other mashup tools. Unfortunately its still early days for Snowy and so isn't all there quite yet. However its GNU's Affero General Public License (AGPL) and built to take advantage of developments like HTML5. So you can imagine how easy it would be to build this into google wave and many other clients. Being AGPL also means it will take a similar route to software like la.conica. I expect there will be services which will host snowy for you such as Canonical's Ubuntu One service (lets not go there now about it) and Apple's dot mac. But you can also host it yourself too, which may work better if your worried about privacy or want to share between a small group of people.
I had no idea Tomboy Notes was available on Windows and Mac too. I had only come across it when I switched to Ubuntu. I also had no idea that there was already a Firefox addon for tomboynotes but I had heard of the Tomboy Android app (which might have been the thing which got me looking a little deeper into snowy). I like Evernote, it works but I'm frankly pissed off with the evernote attitude to the Linux platform. They refuse to create a application because theres not a big enough market, but they create a windows mobile version? They also seem to be about the shiny shiny, I mean a palm pre version but not a symbian or android version? I also expect the Windows mobile version will be dropped soon as version 3 is rolled out. Anyway, I'm also getting frankly fed up of the single nature of it too. You can't share notes and its engineered that way, its part of the evernote philosophy (till a few days ago). I just think although I like evernote, somewhere along the line my relationship with there service is going to get even more broken that it is now. Its bad enough having to run Evernote through Wine or Prism, neither work well and theres no way its just a app which you can leave open.
This is why I think I should just convert to Tomboy notes now and dump evernote. The client is on almost every machine I use, its seemless on the gnome desktop. Theres already API, good syncing and the ability to get linking data versions of the notes. More and more applications are intergrating with tomboynotes. For example Gnome-Do searches and allows me to write notes super fast, Conduit can sync notes and Gwibber now allows you to save messages out to Tomboy. I have seen all types of addons for tomboynotes including the ability to even blog from Tomboynotes (which if it works, will solve one of my long running problems with linux). If I could get Evolution to work with Tomboy, I'll be dancing around the room.
So the long and short of it is that the alternative to evernote via tomboynotes is certainly possible. Some would say, well your missing lots of things evernote does but I'm sure you can either write a plugin for it or even provide a online service for it.