These chunks of information can be tagged and strewn about canvas pages as self contained ecosystems of content. Users can go in to edit them at any time and invite others to view their work. There is, however, no real-time collaboration, meaning that your collection can be shared, but not worked on at the same time.
With Thumbtack, Microsoft seems to have learned that not everyone uses Internet Explorer. To that end, the company now provides a bookmarklet that lets users grab Web content, marking. It gives users the option to tag and preview content before sending it to Microsoft's servers.
The big caveat is that there's no support for Google's Chrome browser and minimal support for Firefox. Mozilla users miss out on the special IE-only canvas view mode, which lets them maneuver their notes around a virtual workspace. Non-IE users are also unable to use the copy function, which lets them temporarily put an entire Thumbtack stack in their clipboard before pasting it into another collection.
Users are given an unlimited amount of storage, which is something that might change, once the service leaves its "technology preview" status. The application handles full-resolution photos from the Web, and Microsoft says video compatibility is coming in a later version.
I worry that Microsoft is introducing Thumbtack at a bad time. There are already a handful of Web social-clipping services that I think do this with far more ease for the end user. More notably Evernote and FriendFeed, both of which have much more intuitive bookmarklets and simpler organizational methods. Worse yet, this isn't taking advantage of Microsoft's existing, and , which lets users store their stuff and interact with each other. This is simply giving them yet another bucket in which to store information.
To Microsoft's credit, moving away from requiring Internet Explorer to really make use of one of its services is a step forward, albeit with removal of two of its most helpful elements--the canvas view, and copy and paste.
If you're curious, here's an overview of how it works: