I've visited an awful lot of systems in the past six months, it makes it a shame that few of them appear on a map. I haven't even made many trips to empire space—appearing in an arbitrary location and having to make several jumps here and there to go where I need—spending almost all of my time instead in uncharted w-space. But I have been taking advantage of null-sec exits to get some red dots of exploration appear on my star map.
My previous map of my travels is clearly focussed on high-sec space. Although there are plenty of treks through low-sec on the side, null-sec remains entirely unexplored. Living out in w-space and scanning for wormholes occasionally offers a relatively safe means of entering and leaving null-sec space, and now that entering a system from a wormhole registers a visit on the star map some new systems appear sprinkled around the periphery of my map.
What is most interesting, however, is the colour of the map. It is almost entirely red, unlike previous revisions. The first time I looked at the map of where I have been I pondered for too long the colours of the stars. It was clear that the size of the dot related to the total number of visits, but the colour didn't seem to correspond to any clear metric. Now that I have spent months away from any of these systems and my map has almost uniformly decayed to a state of minimal activity it seems clear that the colour represents recent activity.
I wondered previously if the brightness corresponded to recent visits, but as I had red dots that had been visited more recently than yellow dots, and orange dots with both older and newer visits, I discarded that idea. But it was a good guess. The brighter the colour, the more regularly the system has been visited recently. It doesn't help my current map look any more interesting, but at least it answers a question that had me confused for a while.