Are there any online platforms where I can play AOE I multiplayer? If anyone is interested in playing how can it be done via ISP?

I might play it sometime. Is this because they took it off zone?

Yes

You can play online using Hamachi network/messenger.
Hamachi - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Hamachi)

Download from here-
https://secure.logmein.com/products/hamachi/vpn.asp?lang=en

Hamachi is actually a virtual LAN created over your ISP. Once you have installed and started Hamachi, you will have to join network for particular game. Like there are separate networks for AOE 1, AOE 2, NFS, CS, etc.

Its little bit difficult to understand at first but will become simple as you use it. I have played AOE 2, CS-CZ and AOM many times using Hamachi.

You can play online using Hamachi network/messenger.
Hamachi - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Hamachi)

Download from here-
https://secure.logmein.com/products/hamachi/vpn.asp?lang=en

Hamachi is actually a virtual LAN created over your ISP. Once you have installed and started Hamachi, you will have to join network for particular game. Like there are seperate networks for AOE 1, AOE 2, NFS, CS, etc.

Its little bit difficult to understand at first but will become simple as you use it. I have played AOE 2, CS-CZ and AOM many times using Hamachi.

BTW you will have to find people to play with you. It can be simple if you are part of social forums like Orkut, etc.

If you need any help you can ask me.