Discourse graphs traffic (available to mods and admins) and since we ported our entire database over, the graphs include traffic from before the move. Posts had a complete drop-off during the move, followed by a big spike as everyone tried out the new software. After that, posts have settled down to the same level as they were before the move. New topics as well as overall posts show the same pattern.
Here are the graphs if you want to see for yourself:
New users had a big spike after the move, which I assume is from people signing up with new names when they had login problems. New signups and new contributors have both settled down to levels above where they were before the move, which is encouraging.
ETA: The DAU/MAU graph is daily active users divided by monthly active users, which Discourse says is a measurement of the board’s “stickiness”. Discourse gives the helpful hint to aim for 30 percent or greater. We were averaging about 30 percent before the move, and are significantly higher after the move.