I mostly work in analytics, so as you'll see, my focus is much more on the research side as opposed to the implementation side.
Your client is New Airline X. They want both link and social shares.
- Pick a few competitors – Delta, AA, etc.
- Get an export of their Twitter followers.
- Get an export of their inbound links.
- Look at who follows your client, has a website and doesn't link to them. That's one target list.
- Look at who follows multiple of the competitors, but not your client. That's another target list.
- Look at who links to multiple of the competitors, but not your client. That's another list.
- Crawl the competitor websites and find where people are linking to broken/nonexistent pages on their sites. Cross-reference with the Twitter export, and you've got a list for broken link building with built in social media information.
If you have access to a large list vendor, you can cross-reference your Twitter list with theirs to see if you can automagically get email addresses for these people so that you don't have to hunt for them, but honestly, I generally prefer not to do that because I don't like the idea of working with list vendors, and too much of their data is just not good.
You can do something similar to the process above with Author Crawler & G+, but I find that it's not as easy to work with, so I rarely go through that additional process.