Topsy’s tools are principally focused on Tweet traffic and link density, which I think are a good indicator of social media presence for these two companies. In summary, Hotels.com is active on social, but is being completely swamped by Booking.com. I think the principal reasons for this are Booking.com’s broader reach (4x more links than Hotels.com), and the significantly larger marking budget that Booking.com brings to bear (as described in each companies respective SEC filings).
521 tweets over the past 30 days, sentiment score of 53, moderate to strong retweet traffic (graph of tweeter traffic per day below)
4,459 links and relinks to Hotels.com
266 tweets over the past 30 days, massive retweeting traffic (graph of tweeter traffic per day below)
17,512 links to Booking.com