I suppose some of my use of digital sticky notes (Notezilla) could be considered a more freeform style of mind mapping. I consider it the external hard drive and backup system for my brain.
I can sort them in columns, rows, stack them, overlap them, sort them into folders, color code them, insert links, images, etc.
What I really like about doing it with sticky notes is that they are very easy to rearrange and I am not locked into one way of doing it.
Best part is when working on tasks, I can pull one out, isolate it, slap it right on my desktop till I finish, then either archive it or trash it, as needed. I can change the color of the note to gray & transparent to indicate it's done.
To remind me to stay on schedule, I can set an alarm on a note and even set it to open a file or application I am going to need at that moment to do that task. Those alarms really help me get things done.