Nah, I still use it. You have to. The tone of voice is non existent. Sarcasm is indistinguishable from stupidity. It's impossible to tell and be right all the time without /s. It's just responsible posting to include it.
Without it, if your sarcastic enough often enough, you'll run into people who unironically agree with you on whatever you've sarcastically said. /s reminds those people who agree with whatever you've said that they are stupid.