When did they start using that? O.o

http://en.wikipedia.org/wiki/Fido_dido

1990s mostly, though he apparently still appears on some things as late as 2010 (but I don't recall seeing him since late 90s)

As for the building you posted, I'm afraid I would never have guessed it, but figured out it was something to do with Disney from the URL. (spoiler tagged the company in case someone guesses it without cheating, having said that Ninpie, you clearly cheated to figure out Fido Dido because as far as i am aware he isn't famous apart from being the 7 up mascot.)

Yeah, I "cheated." I didn't know what he was from and the thread would've come to a hault, most likely. 

You're really close to getting my picture! That's where it is around (Also where my Dad was a Director at.) Keep guessing! If you need help just search it up on Google.

Easy nintendopie,
Atlantis that stupid theme park
or Sea world.

Nope! It's nowhere (well maybe) that theme park; it's by Downtown Disney.

Ehhhh, I thought someone would guess it by now...

What's the answer please?

Apparently it's owned by some company called Blackstone now... that was even more obscure than my 100 year old Siemens logo.
http://en.wikipedia.org/wiki/Buena_Vista_Palace_Resort_%26_Spa

Here's a new one if anyone wants a go... it's a British company. They are at least world famous but it will probably be tricky to figure out for non-Brits unless you know a lot about old computers.