Webwork - 1:19 pm on Jan 25, 2012 (gmt 0)
Parking can provide a traffic test meter and/or "reality check" of a domain's commercial viability.
If you park a domain and it receives little type-in traffic, there are few advertisers targeting the domain name's keyword(s), receives few clicks and those clicks generate trivial income then the domain MAY not be as good or valuable as the registrant assumed it was.
Parking isn't a definitive test of value but it's some evidence.
You can read other threads about how to value a domain by scanning the thread pinned to the top of this forum.
IF parking helps generate income to cover the cost of the domain, whilst awaiting a buyer or development, then I think - at the very least - domain parking is "practical". I followed someone's practical suggestion and, in the early years, my domains were generating $$$,$$$ - more than enough to cover the cost of renewal . . and then some.