I have been using Skitch for a while now and more so more recently for making screengrabs, annotating screengrabs and for sharing them.
In this example I used it to show a member of staff how to backup their course without the user data so then been able to create a fresh version of their course. This makes it much easier for the member of staff to see what I mean.
The advantage of Skitch over using the built-in screen grabbing tools in OS X is that you can edit the screengrab, add comments, highlight areas or even redact sensitive user information if required.
You can of course do all this with an image editing programme such as Photoshop Elements, however the advantage of Skitch is threefold, firstly it does the grabbing as well as the editing and has a bundle of editing tools. Secondly you can grab the entire window, a snapshot of part of the screen, or a delayed screengrab. Thirdly it comes with image hosting, so it’s very easy to upload and share the screengrab.
I have had the free version since it came out and due to my increased usage was considering buying the $20 plus version that has a few more features. Well as of today, Skitch has been bought by Evernote and as a result the plus version is now free.
The plus version has a few more features, the main one is that it can grab entire webpages and not just the part that is viewable in the browser.
So if you have been sharing screengrabs and want more than just the built in version that you get in OS X then get Skitch.