Why companies are not using Social Networking

By now, most companies are aware of Social Networking and have decided to do one of three things:

1. Do nothing, wait and watch (or ignore)
2. Carry out a limited trial
3. Fully embrace social networking

From assumption and experience, I gather that some large companies & organisations have still done nothing because :

• There is no reason for them to use social networking
  (e.g. they are too small, specialised or have no products/services to speak of)
• They are ignoring it, hoping it will go away
• Social Networking sites for brands/products have already been set up already by fans (and can therefore be monitoried and/or influenced in a cost effective way)
• They believe it is too difficult or technically complex to set up
• They have exisiting methods of communicating that do not suit digital technologies
  (I struggle to think who this would be.... but I'm sure they all have their reasons).
• They have been scared off by the transparency and humility required
• There is not a definitive Return on Investment model (ROI).
  Note:
  I was recently told this by a senior marketing type, who had for years used tradional hit & miss TV & Radio campaigns to keep his company just about treading water in its own market space. I had to quote the old Lord Lever phrase at him)

Now some companies, including clients of my company Ideal Interface, have decided to trial social networking sites or set one up in a specially sectioned-off area on their own company website. By creating these destinations they have created useful but still risk-limited efforts where they have started to understand customer interactivity. Some have even adopted a different voice/tone or a slightly different subject from their core offering in an attempt to measure and analyse the public voice.

What's your company's excuse for not engaging?