Contact management, 2017
Many sites have different bonuses eg yahoo can import fb while fullcontact connects with twitter. I don't think its good to leave contacts on only one site , just incase one is down.  I also like having 'hard copy'. I do this every so often.


Mac Sierra
  EXPORT contacts->  all contacts -> edit -> select all (see count change) -> edit export-> vcard
 
  IMPORT to fullcontact (FC) site  ,
    settings -> import , selecting  the Mac-vcard from above
     link your social media contacts like twitter,  and  linkedin  if you wish
    EXPORT     fullcontact site:   backups-> select latest file
 
    IMPORT into yahoo, select contacts icon, select  import contact , add gmail and facebook if you wish
    EXPORT actions dropdown  select yahoo-csv , or mac vcf
   
    outlook IMPORT, select a file from above  and allow to select  a file  , then click upload , located  top left of popup box .  However  there is 2k number of contacts  limit and 5mb file size upload limit.
     EXPORT , outlook/hotmail : manage ->export
   
 IMPORT gmail , more-> import
 export gmail, select all the checkbox, more ->export , making sure to select ALL (third radio button)

 now import the gmail into Mac Sierra, file-> import

This process allowed me to save facebook, linkedin, google+ and twitter contacts and finally all in one file on my mac, where i can permanently store on backup drive

Sharing contacts among your social accounts:

Flow of Contact Sharing

Step	1	2	3	4
Source--->Target (tip)	spreadsheet	----->facebook (find friends->other->select file)	----> spreadsheet of phone numbers that user has made public or friend access to enabled as shown on their info tab on their profile ( account-> edit friends -> contact -> copy paste each 'page' to notepad/texteditor then save -> use spreadsheet program to sort and edit and append to your existing list)
			------>yahoo mail (facebook-> login fb connect)	---->google plus (find-> login yahoomail)
				---->spreadsheet ( export yahoo csv)
				---->gmail (import yahoo csv)
				---->linkedin (add connections-> login yahoo mail)
		--->linkedin (connections->add connections->import desktop)	--------> spreadsheet connections-> export connections , select 'yahoo csv'
		--->yahoo mail (address book: tools->import)

Comparison

service	export	import from email service	import by file
linkedin	y	y	y
gmail	y	y	y
google plus	n	y	n
yahoo mail	y	y	y
plaxio	y	y	n
twitter	n	y	n
hotmail /live /msn	y	y
facebook	n	y	y