It's a site for finding 1v1 practice partners in Dota 2.

1. Sign in via Steam
2. Add heroes that you want to practice (and against which heroes)
3. Press "Find match"
4. dotapra.cc matches you with a partner and gives you his/her steam ID
5. You invite him/her to a dota 2 party and play as much as you want
6. Whenever you feel like practicing your mid laning, GOTO step 3