By Kyle Lagunas, an HR analyst at .

Everyone loves perks, right? Catered lunches, an open vacation policy, and access to a concierge, all sound really nice – especially if you’re asking me to work 70 hours a week. Beyond the fun and games, though, how do you motivate your team and inspire loyalty every day? In recent years, the most successful start-ups have focused on offering their employees something more: a connection to the company. Three prominent startups – Groupon, Zynga and Dropbox – are each cultivating lasting company cultures, and I’ve taken a look to see what’s working and what’s not.