The 37 Signals answer is a good immediate reaction, but there is some due diligence that Google can do here, that can be used for longer term product development, as well as a sanity check of the current state of their product:
* Review the original intent with the 10,000 limitation. Was it a precautionary measure that turned out to either be justified or incorrect? Was it a technical limitation that has since gone away with DB, browser or bandwidth improvements?
* Ask the customer about their usage patterns. Can they be served with an alternate, existing product (LDAP, mailing lists, Google Docs spreadsheets)?
* Run some stats on a sample user base and project what percentage of other users will hit this limit at what point.
* Is there an opportunity to develop a new product, not for this user in particular, but something that uses contacts in a different way for those users who have a legitimate need for this many 'contacts' (large mailing list support within Gmail)?
* Start logging the number of users with this complaint internally, so that demand can be measured even if the user doesn't file a feature request.
Regardless of whether you personally think someone can maintain 10,000 relationships (they certainly can't), you can always learn from the unexpected ways other people use your product, and figure out a way to either improve it or create a separate product that can interact with it.
* Review the original intent with the 10,000 limitation. Was it a precautionary measure that turned out to either be justified or incorrect? Was it a technical limitation that has since gone away with DB, browser or bandwidth improvements?
* Ask the customer about their usage patterns. Can they be served with an alternate, existing product (LDAP, mailing lists, Google Docs spreadsheets)?
* Run some stats on a sample user base and project what percentage of other users will hit this limit at what point.
* Is there an opportunity to develop a new product, not for this user in particular, but something that uses contacts in a different way for those users who have a legitimate need for this many 'contacts' (large mailing list support within Gmail)?
* Start logging the number of users with this complaint internally, so that demand can be measured even if the user doesn't file a feature request.
Regardless of whether you personally think someone can maintain 10,000 relationships (they certainly can't), you can always learn from the unexpected ways other people use your product, and figure out a way to either improve it or create a separate product that can interact with it.