It is an opportunity to network with corporate. During summer training, one interacts with several corporate at different levels. Making a good rapport with them can go a long way in helping your corporate career.
When I say that, I do not mean that one should exchange business cards and start sending out CVs immediately after you go back to college. Things like thanking all the corporate you have met and who have helped you during your summer training by sending out an e-mail is considered a good gesture and starting point of future relationships. In fact if your organization permits, sending a synopsis of your project is also not a bad idea.