There will always be issues with URL matching using regex as some cases simply can't be caught with regex. An example where regex will fail is including brackets in URLs but only when the brackets are opened within the url:

• Include brackets: http://<domain>.com/foo(bar)
• Don't include wrapping brackets: (http://<domain>.com/foobar)
• Include commas: http://<domain>.com/foo,bar
• Don't include trailing commas: http://<domain>.com/foo, other text
• Detect spaces (paths are ambiguous?) c:\Users\X\My Documents