I have to admit that since very very recently I kept 5 very different address books: 2 on my phones (on from Slovenia and one from UK), one in gmail, skype and Thunderbird. Then I got an Android smartphone and decided to merge everything together.
- I copied all phone numbers from both SIM cards to my Android phone book.
- I did the same with Skype contacts (synced Skype contacts with Android phone book).
- I installed an add-on in my Thunderbird to sync all contacts to gmail
- I synced my phone with Gmail
- In gmail I merged everything together. Voila!
But it could be more simple.
Remember Xobni. An academia project that made it into Outlook? They released Smartr for gmail and phones. It integrates all contacts from social media sites, phone books, address books together in gmail. It also shows some insight at rhythms of conversations with your contacts. Nice!
May be also of interest: