Knowledge of your customer's industry classification can be crucial in customer analysis, market analysis, customer segmentation from a marketing perspective and proper account portfoliomanagent.
There are quite some standardized industry classification systems available, some local, some global, like ISIC, NAICS, NACE, SIC, GICS etc (source: Wikipedia)
Depending on the one you choose of course, you will need to manually maintain the structure at least once in your SAP CRM system.
This can be quite a job if you for instance choose for NAICS (19.745 different classifications).
If you have SAP CRM and SAP ECC, you can double the customization... Sure?
Once maintained in either system, you can synchronize the full (or part, but I would recommend full) industry system customizing between the 2 systems.
Log on to the system where you want to download the data to.
Go in to the IMG.
SAP Customizing Implementation Guide -- Cross-Application Components -- SAP Business Partner -- Business Partner -- Organizations -- Maintain Industry Systems and Industries
Here, in the menubar, choose for utilities-> adjustment
In the popup, choose the RFC destination where you want to download the data from.
The next screen will show you the comparison between the 2 systems.
Select the system you want to download and click on the button 'adjust'.
In the next screen, click the button 'All'. Save the changes and choose or create a transport when asked.
Now go back to the industry system customizing, and notice the industry system has been created.
Go to the contents of the industry system by selecting and clicking on the left side of the screen.
The contents are still empty. Now, again select utilities->adjustment, select the RFC destination, and click OK.
The system will give a summary of the comparison. Click the green checkmarkbutton to continue.
You will now get a list of all the data in the other system.
Now simply select them all (either tick them one by one, or choose edit->select->select all and go home early) and click adjust.
Now again click adjust all. Save, transport, and done!