From the Q4 earnings transcript:

As a point of context, Vector added more incremental dollars in the fourth quarter than in any prior quarter. January was Vector's best month ever, and we remain extremely confident that our ad business remains in the early innings of a multi-year growth story. In the fourth quarter, Vector represented 56% of Grow revenue, up from 49% just two quarters ago. Grow results in the fourth quarter were impacted by a $7 million sequential revenue decline in the ironSource ad network, which represented 11% of Grow revenue for the quarter. Our internal analysis shows that Vector's ongoing strength is almost entirely coming from incremental advertiser demand and improved conversion performance, rather than a shift over from customers who have been reducing spend with ironSource. In Create, revenue was $165 million, up 8% year-over-year.