I've been using Trackbear since the beginning of November, where I joined a leaderboard for Pillowrimo. I've only created one project, TSW outlining (basically, finish the outlines for The Sundered Worlds), but I suspect there will be many more projects in the future.
I like how I can link goals to projects. My goals for November and December were, respectively, Write 10,000 words and Write 6500 words. Both are linked to the TSW outlining project, so I can see how much I've written toward that project over the past two months.
I haven't yet tried to link a goal to two projects, though I'm sure I'll try to do it in the future – if it's even possible, that is. I haven't figured out all the functionalities of this website, yet.
It's a very simple website, but that's really all I want. All I need is something that allows me to track my progress per day, whether that be words, pages, or chapters, and Trackbear does that very well. Unless the website interface changes drastically, I can see myself using it for years on end.