How many sites is it safe to add to webmaster tools?
I have about 10-15 but at the moment only added 1 in webmaster tools so is it ok for me to add the rest or am i risking telling google i own them all.
Likelihood is that Google already know you own them all unless your extremely careful and good at hiding your footprints.
Do you use any other Google products which such as Analytics's on all the sites ? are the whois hidden, are they on the same servers or IP ranges, do they follow the same template or design structure, are they interlinked..................There are lists as long as your arm which would resemble a footprint in some form or another.
You'd have to be super duper Anally retentive for them to not already know or be able to work it out with out much of an issue if they really wanted to hunt you down...........like James Bond style secretive lol.
I suppose it really comes down to what you think your going to lose by adding them and what your gaining, I have 3 or 4 Webmaster tools accounts with between 15 - 40 on each........Personal , business, clients etc. The only reason they are separated is ease of management otherwise they would be all in the same account.
I always think that when you make it obvious your trying to hide something or you slip up....thats when you come unstuck.
Plus have you never thought that if you keep your nose clean your own personal reputation/authority may have an impact on those sites associated with you ? Guess if your playing in shady areas thats maybe your concern about adding them ?