A digest email is great way to get people back to the forum because the thing that will draw them in most are the topics that interest them - not a count of the number of total posts or threads - which may actually put people off (too few and people may think what’s the point, too many and they may feel they don’t have the time to go through them all).
The most important stat from the header that is likely to draw people in is the number of their notifications - the others can be added to the bottom somewhere (if needed at all). So the logo could be moved to the left and the notification count (perhaps with an icon) could go on the right.
I just want to add that we shouldn’t try to ‘force’ people on to the forum, instead we would be better of catering to the needs of our users and allowing people to use the forum in whichever way suits them personally. This means, make the forum experience great for those who want to visit the forum. Make the mailing list mode great for those who want to use that and for those who don’t want to, or have been too busy to visit daily (or even weekly) provide them with a digest email that not only highlights the ‘top’ posts and threads but also shows them what else has been going on via a list of the latest threads - because it’s very likely a topic might catch their eye that they’re interested in and if it weren’t there to begin with then this opportunity would have been missed.
For all this to work the email needs to be easy to absorb quickly and without much cognitive energy - or people will start ignoring it and/or hit the spam button so they don’t have to see it anymore.