A new required field has just been added to the user registration form. The "Reason for joining" field used to exist on the forums registration page, but the data could not be brought over when we imported users from the old site to the new. Well now it's back, and as a required field it must be filled if you want to make any changes to your user profile, such as uploading an avatar, changing your notification settings, etc.
If the field is left blank, you will get an error message when you try to edit your profile. Don't worry, just add a couple words like "Volunteering" or "To foster", then save. Your answer doesn't need to be elaborate or overly precise. The purpose of the field is mainly to weed out spammers and prove you're human at the time of registration :) Answers are not public, they are only seen by the admin and by you when you edit your profile.
As ever, if you have problems, post a comment here or message me using the contact form.
Thanks!