It's not spyware because
1. You have the option to install it or not. It does not sneak onto your computer or come bundled with anything.
2. You have the option to run it or not.
3. While running it, you have the option to allow it to track or not.
4. You have the option to not allow it to track web apps.
5. You can hide any data you don't want shown, any application you don't want anyone to know you are using.
6. You can hide your whole profile and keep it private, for your eyes only.
7. You can delete all your data from your account. (I exported my data and deleted it to start fresh, when I got a new pc)
8. You can delete your account, itself.
Though what does bother me is the fact that there's no way to block someone from following you...
Are you aware that people can follow you without you knowing it (if your profile is public), just by subscribing to your RSS feeds? Even if you could block a user on the site, what would be the point if he could just grab your public feeds and follow you from a feed reader, rather than the dashboard?
Of course if you make your profile private, they can still follow you but there would be no point in it. They can't see your data and you have no public feeds.