Yammer was called "Twitter for enterprises, or Twitter with a business model", he recounted, but it is evolving into a larger service with more collaborative support.

As far as Twitter goes, David doesn't see them as a direct competitor, since it is so geared to open discourse. Selling private areas for business discussion doesn't fit with that model, he feels, so Twitter might not go there ever. Yammer, on the other hand, is geared to privacy as the default, which makes more sense in the business context.

Yammer also dropped the 140 character limit that defines Twitter, and which makes sense for a consumer and SMS-integrated product.

David points out that the buyers of technology in the enterprise market are not necessary the end users. Yammer has developed a wide range of administration tools -- privacy, usage policies, user management -- that appeal to the IT buyers or management. But end users really want to use web 2.0 style tools even while at work.

Yammer supports 'bootleg' adoption, since anyone with an 'company.com' email address can start using the product, so it doesn't require corporate sign-off, but the admin tools do.

David has found a greater willingness by users and management to try new SAS models, which favors start-ups and leads to innovation.

Businesses have clearly come to the realization they shouldn't necessarily own or manage their own software, David thinks. But the hybrid, viral model that comes with a product like Yammer means that companies don't have to make any decision about buying until it has become widely used and popular.

Yammer seems to have an immediate impact on the way work gets done. In his experience, in traditional large companies people really don't know what people are working on. "If you think about how tools like Facebook and Twitter allow people to remain connected with large groups of friends, and think about how that could work in business, I think its going to make companies more efficient [...] and they will have much more engaged employees because the employees will feel much more connected to their colleagues and what is happening in the company."