The recommendations on the IFDB home page are "algorithmic" - they're picked by the computer based on statistics in the database. They're not paid ads - they're based purely on ratings from our members and review sites like Baf's Guide. We're not being paid to promote one game over another.
The system picks front-page recommendations by randomly selecting a few games with the highest ratings, excluding games that you've told us you've already played.
We determine the games with the highest ratings using Evan Miller's formula, which we call "starsort".
We used to sort by average rating, but this would tend to rank games with just one perfect 5-star rating above games with dozens of 5-star ratings and a few 4-star ratings. Evan Miller's formula sorts by our confidence in the game, by adding five "fake" ratings to the average (one 1-star, one 2-star, one 3-star, one 4-star, and one 5-star rating) and subtracting the standard deviation from the result.