There are phisher bots that invade forums and other sights looking for contact information. If you post your phone number as (206) 555-1234 , those bots will grab it and someone will have your phone number. Perhaps tomorrow you start getting annoying phone calls from telemarketers in Singapore, or someone uses the phone number to find your address and you get uninvited guests at O:dark:30.
They can do the same thing with your email addy. That,s why many people refuse to put their email on the net or disguise it like the phone numbers. It's basically a self protection thing.
Joe