For those of you unfamiliar with it, the Data Importer is a Sitecore module on the Sitecore Marketplace. It's a tool that allows you to import data into Sitecore. It was originally built to import sites from existing websites by pulling from databases and into content items. It allows you the flexibility to handle each individual field in a row of data using a number of built-in conversion types but also allows you to extend the system by creating your own providers for data sources and adding your own field conversion types.
update on 9.13.2011 - Sukiyoshi's open source license has changed to the MIT open source license.
update on 3.8.2012 - Sukiyoshi has been updated to work on Sitecore 6.4 and up and has a specific release for it you can jump over to the Sukiyoshi open source repository for the specifics.
Over the past few years I've been fortunate enough to have had the opportunity to work with Brightcove and was given a development account for their platform that I could work against. In that time I went and took the existing .NET SDK Tanaris that had implemented the video read methods and blew out the rest of the read and write methods for the videos and playlists. I ended up learning a lot and had started my own branch of the code. I named it Sukiyoshi, after my wife. I did a lot of work on Sitecore sites at the same time and after having built More Interop with Douglas Couto, which used a lot of video, I realized that being able to outsource the video management aspect of a Sitecore website could have greatly simplified our task.
updated on 8/11/2011 regarding the order of the tabs. specifically to the position of the content tab .
So during the course of developing websites for Sitecore there are a lot of opportunities to create custom functionality. One feature that I like to use is a custom editor tab. If you're unfamiliar with the concept then you've seen them and just didn't notice. If you have a media folder selected you'll see options to "upload" or "upload advanced".