Microsoft's campaign ended after a total of 1.25 million views, totaling a pay out of $3,750. That's not a huge amount of views spread across multiple YouTube videos, which is why the campaign started on January 14 and ended on January 16.
As Ars Technica points out, the practice feels shady as hell, but on the surface it appears perfectly normal. Paying for promotion is just advertising; the problem surfaces when you look at the leaked legal agreement behind the promotion. The agreement states that participating partners "may not say anything negative or disparaging about Machinima, Xbox One or any of its games in your campaign video." Again, not entirely unexpected for a paid promotion, recalling the situation with Riot Games and its Pro League of Legends players. The real kicker is this section:
"You agree to keep confidential at all times all matters relating to this Agreement, including, without limitation, the Promotional Requirements, and the CPM Compensation, listed above. You understand that You may not post a copy of this Agreement or any terms thereof online or share them with any third party (other than a legal or financial representative). You agree that You have read the Nondisclosure Agreement (attached hereto and marked as Exhibit "A") and You understand and agree to all of terms of the Nondisclosure Agreement..."
Keep reading at US Gamer.