Hi Revellion - hope you're keeping well!
It's the end/start of a new quarter, and that's when ad agencies and companies advertising in the online space start budgeting again for the next quarter. Typically the spring is the lowest net-spend by companies industry wide, with the highest ad spends happening around the 'black friday' shopping holiday and the December-January holiday period 🙂.
There's also economic factors that contribute to companies ad spending, something to keep in mind.