We know about the WSG marks from a blue post a couple of weeks back.
We also knew from a blue post (no specific details) that waylaid supplies were being changed a bit and would also give increased exp.
EDIT: The Waylaid supplies notice was in this News article:
" It is Not too Late to Join in Season of Discovery
For players looking to catch up with their friends above level 25, we will be implementing a 50% experience buff for players between level 1 and 25. Players will also see an increase in experience gained within the Blackfathom Deeps raid dungeon when it is cleared. The raid dungeon will still continue to run with the current lockout timer, and players will no longer gain the world buff beyond level 39, however.
Waylaid Supplies will also see an adjustment, we will share more later, but there will be a significant increase in experience gained from them on turn-in."
Literally 2 weeks ago: jan 23