I think its good that soma is already listed, even on ether delta, this exchange is not so user friendly but at least it is decentralized. And remember that soma will be listed on other exchanges after the ico.
As i know, every coin based on Ethereum platform is automatically listed on Ether Delta, so this is not something big. Let's wait for other exchanges, because on Etherdelta trading is almost impossible. People keep there only dust

No that's doesn't seem to be true. There are quite some tokens I hold which are not available 'yet' on EtherDelta.
To get it listed :
How to list a token:
Any Ethereum-based token can be imported as a custom token and start trading on EtherDelta, without permission.
To appear on the list of official tokens, the token owner/creator should PM me with the following information:
a. Token address (code should be verified on Etherscan)
b. Official Web site (the token address should appear on the official Web site for verification)
c. Paragraph description of the token.