I really like being able to link your xat username and ID to your forum profile, but what's to stop someone from putting someone else's or a false ID and/or Username as their own?
There should be some sort of Username and ID verification so no identity theft, scamming or phising can occur. The easiest way for xat to implement verification is make it so when a user logs in to their xat account (not forum) and scroll down to "more", there's a box to put your forum username. After linking your forum account to your xat account a notification would appear on your forum profile asking you to confirm the link. After confirming, your ID and Username would automatically appear on your forum profile. To remove the profile link, a user would have to make the box blank in the forum username box under "more" settings or detach it via "edit profile" on their forum profile.
Edit: People who don't support this idea may use the argument that moderators can punish people who impersonate others. How would you know to report someone if you don't know they are impersonating someone else? Verification would prevent impersonations from happening in the first place.