How to get OpenID user Profile info?

After logging into SO, my nickname shows up at the top.

When I set up openid on my site, I do not get any profile information.

I tried implementing OpenID using openid-selector and Zend Framework

The response parameters I get:

openid.assoc_handle B2Jgsdf7jkDsdfUwWBGMHUshLmavymH...
openid.claimed_id   https://me.yahoo.com/MyYahooId#50a9f
openid.identity https://me.yahoo.com/MyYahooId
openid.mode id_res
openid.ns   http://specs.openid.net/auth/2.0
openid.ns.pape  http://specs.openid.net/extensions/pape/1.0
openid.op_endpoint  https://open.login.yahooapis.com/openid/op/auth
openid.pape.auth_level.nist 0
openid.pape.auth_level.ns.nist  http://csrc.nist.gov/publications/nistpubs/800-63/SP800-63V1_0_2.pdf
openid.pape.auth_policies   http://schemas.openid.net/pape/policies/2007/06/none
openid.realm    http://mywebsite.com/
openid.response_nonce   2009-10-28T18:23:05Zyj0aF9sdfsdfCmoegeAiQ--
openid.return_to    http://mywebsite.com/
openid.sig  U9O4UpuPsdfdsfsdfBHbVLdjiSyo=
openid.signed   assoc_handle,claimed_id,identity,mode,ns,op_endpoint,response_nonce,return_to,signed,ns.pape,pape.auth_level.ns.nist,pape.auth_level.nist,pape.auth_policies

What is the reason I do not receive profile information such as nickname? When SO uses openid-selector, how does it get the nickname?

Any information aside from claimed_id and endpoint URL must be retrieved via Simple Registration (SREG) or Attribute Exchange (AX) extensions to OpenID.

You must explicitly request for them when asking for authentication.

Zend's consumer SREG documentation can be found here: http://framework.zend.com/manual/en/zend.openid.consumer.html#zend.openid.consumer.sreg

Note that these information are not guaranteed, and providers are given the freedom to decide (with or without user input) to withhold any and all requested information, or not support them outright.