First time i am hearing about this. I really don't know about any type of masking.
URL masking can be done quite easily in a number of ways. The most reliable method i've used is using a DNS service and nameservers of a hosting company (Godaddy offers this service) to forward one domain (the one you want to visitor to see) to another (the one that is being masked). Other methods include using mod_rewrite (for Apache servers) or inline frames / framesets in HTML. Google "domain masking" for tons of resources and other methods.
URL masking is covering up a URL with a different on. It presents one URL when the actual URL is something different. share your feedback.
Can you elaborate about a bit more what actually URL masking?I am googling about how its possible to make a URL masked one.