The Diptera.info site has been targeted by spammers during the last few days. Luckily, because the site uses a system where new users need to be activated first, you did not notice this at all. All created spam accounts were deleted. However, the amount of bogus accounts caused considerable extra work for Chris Raper and me who deal with the new accounts. Changing the verification system to a more advanced one hardly resulted in a let off. For that reason I decided to disable the registration system for the time being. I know it may cause some hassle and delay for new users to write to the webmaster too ask for a new account but it will be much easier on us as administrators.
I apologise for any inconvenience this may cause but I hope we can go back to business as usual soon.
Update (5 Sept. 2012): I have noticed on other sites with the same registration system that the flood continues so for the time being no automatic registration. On one of the sites I have installed another security system. If that has the desired effect it will be installed on this site as well.