Is there any way to improve verification to prevent bots from signing up?

[Alpha Baymax]

I've noticed that a lot of them sign up here and then spam unwanted advertisements. A lot of sites have verification to prove you're not a bot.

 

[Oracle Spockanort]

I’ve already reduced the amount of them by 90%with all of our spam tools. You’re seeing 1% of what is actually coming through.

When you see spam, please report it.