Does sharing a loyalty account increase your targeted offers?

Let's say there's me and my friend. We want to get the most/best targeted offers from a grocery or big-box store. Would it make sense for us to share one account on the store's loyalty program?

I'm guessing that the answer is it varies, it depends on the situation/store, and nobody really knows. But are there certain factors I should consider when thinking about this question? Anybody out there with relevant experience?

My general approach has been to just have my own account for each store, but that's only because it's easier for me that way.

I know that I've gotten some great coupons in the mail from a store after I didn't shop there for a while, so I was thinking maybe they were trying to get me to come back (if so, it worked). If that's the case, then maybe sharing a loyalty program would have hurt my chances of getting those. I have no idea.