Why Must I Give My Phone Number To Log Into My Account?

I Never Had To Give My Phone Number In The Past To Log Into My Account . If I Post A Add On Craigs List Will My Phone Number Appear In My Ad ?

That web site has had so many serious criminal problems the phone verified accounts became necessary to trace users.

http://hubpages.com/hub/Phone-Verified-Craigslist-Account

Craig's List implemented the phone number system nearly a year ago due to a huge under-age child prostitution issue the site was dealing with. Under age prostitutes and their pimps would post claiming to have just turned 18 and, well, you can figure out the rest from there.