Your Company Networking Event: This could be as formal (professional dress code) or in-formal (Holiday party anyone?) as your company is. If everyone comes to work on a daily basis in suites & ties, and/ or suites & heels, then your Company Event will be more of a formal nature, all intra-office rules apply. Don't think every Company Network Event is another office party! If alcohol is served, by all means -- limit your intake! Bring your ideas! Do not bring negativity! Bring the answers, someone may be listening.
A Social Network Event: These regularly meet at a local restaurant or other relaxed venue with hors d'ouevres and coctails available. Bring plenty of business cards, a small appetite and socialize, socialize, socialize! At the last Social Network Event I attended (at a local Chili's Restaurant,) I chatted with a local judge, a housepainter and the chairman of the local social action committee at the same time! That was a lively and very friendly conversation.
A Professional Organization Network Event: i.e. IAAP. There are many very different professional groups out in Network-land, some are gripe sessions (you can tell within minutes if you have wandered into a gripe-fest). Most are extremely informative and supportive groups of people with the same goals as you, basically all attendees are striving to be successful in the chosen field. These events are similar in nature to the Company Networking group, the caveat being that all "forensic accountants" don't work at the same company, but they all have stories to share and learn from, of course, never breaking professional confidentiality.
Then you have the Professional Executive Network: This is perhaps my most favorite group to meet with. I have attended several different PEN groups and find there are two separate formats for this style of Networking group.
The first is a buy-in group, you pay a membership fee, there is no exclusivity (you could have 3 graphic designers and 4 dry cleaners in the same group.) They have group activities as well as the regular Networking meetings. There are several nationally sponsored groups of this style and they are very successful.
The second group I have attended has been as an invited guest. This was a very intimate, warm group of business owners and professionals with success for everyone the group's goal. It is exclusive in that there will be only one of each business type as a member. What I mean is that there is one Web Designer, one Business Consultant or only one Virtual Assistant (if they will have me! hint hint). Everyone brings one invited guest to the regularly scheduled meeting, you get a very real opportunity to learn all you need to know about each person involved. My best referrals have come from this group!