I just helped a friend go through this, and I think in a matter of months this type of stuff will just deal with itself – but for the time being, if you are super depressed by the idea of all those lovely FB likes going away, but you are a WordPress guy or girl and not a developer, here’s what you do (as you can see, I don’t really care all that much):

Make sure it’s a real 301 at the .htaccess level (they have plugins that let you modify them – which is actually kind of scary) and not a WordPress ”best guess,” in other words, makes sure it’s: oldsite.com/page1 301′ed to newsite.com/page1, instead of newsite.com/page-one

Then basically you put the button inside the post on the page using the OLD URL – but since you probably use something like getsocial like I do – and editing that URL is not possible without doing surgery deep inside the plugin editor or one of the more terrifying plugins like “search and replace,” you do it the hard-ish way for the posts you care about

Step one – Figure out which posts you care enough about do do this on

(There may be a smarter way to do this – this is just the way I did it – so by all means keep reading the internet).  Pick the posts that have enough likes that you just can’t stomach losing them.  Then:

Turn the get social plugin off for that post only – or whatever social button plugin you are using (if you cannot turn it off post by post then this article will not help you).

Step Two  - Get the button for the OLD URL and put it on the NEW site

To do that, go here:  http://developers.facebook.com/docs/reference/plugins/like/?locale2=es_ES  remember to put in the OLD URL not the new one.  I have no idea why this is in Spanish – I’m in Shreveport Louisiana when I did this… but whatever ignore that if it happens to you doesn’t matter.

You should see the FB shares from the old posts – YAY!

For the posts you don’t care that much about just hope that they migrate and end up passing it through automagically – which I think is a reasonable possibility.  Here are some other helpful links:

http://www.stateofsearch.com/the-problem-social-buttons-301-redirects/

http://stackoverflow.com/questions/7691311/facebook-like-count-resets-after-a-301-redirection

http://stackoverflow.com/questions/3823676/is-it-possible-to-force-facebook-likes-to-follow-301-redirects

http://searchenginewatch.com/article/2172926/How-to-Maintain-Social-Shares-After-a-Site-Migration

Now how to do this for G+/Twitter… sigh – about to go figure that out now.

I am certain this post has both a massive quantity of typos as well as factual errors – if you know something I don’t please comment I’m curious about any smarter ways to do this or just things that are smart in general.