There have indeed been some recent changes due to the large influx of undesirable new elements under the registered members - of which disabling links in signatures was one. The permanency of each of these is not set in stone just yet, and your input on this part is noted herewith.
In the meantime, you can of course still add it as your website.
EDIT: although it would appear the ink is still in you signature, albeit in an aesthetically less pleasing way.