Face Book is a huge tool for businesses today! Glad to see you jumped on and I liked your page! I get all my brewery news form FB and love it. I find out about all the special events and offerings, beer festivals, brewery schedules etc. as already mentioned, when traveling I look up local pubs/breweries to find out what's going on as well.
For the brewery it is easy to create an event and send it out to all those that have liked your page, people then share these events and word spreads rapidly. I can also find out about collaborations that are taking place between breweries, seasonal brews and pictures are always fun to see as well.
I know some breweries that have one person that does nothing but manage social media on staff to handle daily postings, replies to inquiries, posting pictures and linking blogs/twitter feeds and anything else that will drive business their way.