I agree to use Steem for promoting other coins. We have some examples here, like SmartCash, which uses a special Steem bot for SmartCash related content. I think this is the way to go and we will see special crypto communities here on Steem in the future. I am actually building an app called 1UP that could help with that although I haven't really intended it for that. My focus personally is more on the Steem communities but it works for all.