Lawrence Wilkes of the CBDi Forum has written a paper called Inside Every Web Service is a Benefit Struggling to Get Out (free registration required). He has some very specific benefits. In the intro to the paper he says:

Things like "improving business agility", "reducing time to market", etc are still valid - but not entirely new. Why is Web Services going to deliver this time? Consequently, there is a real need to be much more precise about the specific cost savings and benefits for both business and IT that can reasonably be attributed to Web Services.

Wilkes makes the distinction between "conversion," doing what we do today differently, and "exploitation," doing innovative things that we couldn't do without Web Services. Most early uses of Web Services are going to be in the conversion category, but the really interesting stuff, in my opinion, is in the exploitation category. I don't think we've begun to envision the changes that standard interfaces and routable messages will bring.

Wilkes lists seven features of Web Services and the benefits that follow from each feature. I'll list them here, but you really need to read the paper to get the full effect. He breaks them down, in some detail, by benefit to the business and benefit to the IT organization.

1. A simplified mechanism to connect applications regardless of the technology or devices they use, or their location. This leads to business process efficiency and IT cost reductions.
2. Based on Industry Standard Protocols with universal support. This leads to costs reductions and choice.
3. Leverages the Internet for low cost communications. This lowers the barriers to entry for connecting to trading partners and simplifies middleware.
4. Loosely Coupled. This creates agile relationships and reduces maintenance.
5. Supports Multiple Connectivity and Information Sharing Scenarios. This supports costs savings through consolidation.
6. Self Describing. This reduces time to market by shortening development cycles.
7. Automated Discovery. This increases the size of the "ecosystem" and increases automation.

I would argue that most of these benefits are on the "conversion" side of the argument. Some, of course, cut both ways. The benefits of the 'exploitive" side of Web Services are difficult to quantify since until the innovation happens its difficult to imagine what it will be. I plan to talk about one "exploitive" use of Web Services later this week.