A question I had to ask myself today was if a POS system or a Parcel tracking system can be considered an MES system or not. I know that naming does not matter, but we've been telling people in industries that the system that integrates ERP systems and operations systems is called MES and have pictured this heavenly world for them were some planning or order in ERP translates into automatic operations down in filed level.

If you are a logistic company and you get orders for moving bulk material which then gets executed by your truck drivers and equipment operator, and then you feel like you need some system which translates these orders into individual truck/equipment operations that can be executed automatically and execution results can be recorded against original order then are you talking about an MES system? Should you approach the most well-known MES solution provider and define that as a project for them?
Or are you talking about the same old custom software that runs your business?

I've started working on a massive MES project that involves hundreds of sites and a big SAP system as ERP.
While we were trying to identify business drives and project objectives the customer pointed out that "Having an MES would be the only way to give our large organization competitive edge over small businesses".
Currently every few site in this organization operates very similar to a small business. Of course this makes the organization very agile and flexible but at the same time not better than any small business competing with them.
If they can link their SAP to order executions in Sites, then potentially an order from customer can be fulfilled with resources available in any of sites. This should help them

1. Have lower quotes
2. Full fill orders that single small business can't
3. Provide equivalent or better flexibility to customer to edit orders

 This is exciting to me, as this is probably the first project for me where MES is a necessity to survive. At the same time it also mean unprecedented stress.