Certainly not abandoned, but perhaps biding its time - the old Forum http://www2.theiet.org/forums/forum/categories.cfm?catid=205 is still active, so a lot of the activity is still happening over there rather than here. I gather the 'jury is still out' on when the switch-over will finally occur.
With any luck, I've finally lost my old pseudonym. It started off when the IET required a user name and password to view some parts of the web site, so I just picked something I could remember. Then they started linking the user names to membership accounts. Then they became the forum user name. By that time, it was too late to change it.