What do you think guys? do you knew that tobi was in fact.... well kakashi old pal?
We don't know that yet.
Yes it's heavily implied..but it's still an unknown until Kishimoto explicitly tells us. :3
After all..Obito could be one of the many names he uses.
Because don't forget, "Tobi" was also the one who unleashed the Kyuubi on Konohagakure in the very beginning of the series, something that Obito couldn't have done, what with the whole face crushing, as well as being too young at the time.