I use Tiny Tiny RSS for reading feeds, and I want feed subscription to be as easy as possible. My new SubToMe plugin for Tiny Tiny RSS allows you to register your TT-RSS instance at subtome.com, making feed subscriptions a two-click process.
Enter the TT-RSS preferences. That's it; your Tiny Tiny RSS instance is registered with subtome.com now.
When clicking a subtome-enabled follow button, you'll see the following popup window: