There is a difference between attending a working event (where everyone is there to meet people, make contacts and introduce their services to others), and social or group events (such as a little league dinner, non-profit luncheon, etc.).
If at a networking event, then an exchange of cards and a brief sharing of each others' services is appropriate. I recommend approaching these networkign events with an open mind with the potential for opportunities that I might not have pre-thought out, e.g., don't network with the mindset of "getting something out" of someone....you will often be disappointed. However, if you go with the minset that you are there to explore the possibilities and meet people, you'll be surprised at the connections you make and the opportunities that present themselves. At the very least, at such events, you should provide each new connection with: 1)Your name, 2) what you do, 3) what geographical area you serve, and 4) I encourage you to ask about their business and also be sure to ask "Who do you know that's thinking of buying or selling real estate?" and finally, and most importantly, ask these questions of people: 5) "what are you looking for or hoping to find at this event?" and "How can I help you or your business?"
If at a social or non-profit event, where discretion is more appropriate to the event theme, you should be asking people around you...what do you do? and How long have you been involved?....that usually gets them to reciprocate and ask you the same. Answer with a limited amount of information that includes: 1) what you do, 2) what geographical area you serve 3)who you work for. You need to be careful in this environment to not appear to be "working the room."
Good luck!...And by the way...Who do you know that's thinking of buying or selling real estate in the San Francsico Bay Area? :)