What performance issues can I expect when accessing a remote database vs a local database? All the files are local and just the database will be hosted on another server/domain.

If I distribute an web application, that potentially thousands will use on their own domain, what performance issues can I expect because all these applications will access the same remote database?

What recommendations do you have on setting up the remote server to handle the requests?

Performance will depend largely on how remote the database server is from the web server and on what type of connection they have.

I'm curious as to why you would distribute the application in the way you described. Why would you want thousands of web servers connecting to the same db? In that case you certainly will have no control over the type and speed of connection between the web servers and the db server.

Instead, why not give each of those users space on a shared web server that's tightly clustered with the db server? Or create the application so that they can each run a personalized or branded version in the same web server space.

The reason for considering this more conventional architecture is that when the db server is clustered with the web server(s), they're typically on the same rack with a Gigabit (or better) connection, so you have optimum performance.

HTH.