Max, what do you mean by autologin? Storing their info in a cookie to allow instant access from the same computer? If so, then it's a good idea. Some people check forums many times per day, and logging in each time would be discouraging for these frequent users. It's good to offer users the option with "Remember Me" checkbox so that if they log in from a public computer they don't inadvertently leave it logged in.
Or, if I missed the point, can you explain what you mean?