You can adjust what you receive through your settings tab. Here is the full explanation of the Family Activity and Genealogy Feed emails:
Family Activity Feed
Once a week we send a summary of the activity in your Watchlist.
We also include Thank-Yous you received that week as well as birthdays in your Watchlist coming up the following week.
This goes out to everyone watching any profiles, but only if there have been changes by others besides yourself.
You can opt-out of these updates on your Settings page. However, you should not opt out if you're a Wiki Genealogist who has signed the Honor Code.
Wiki Genealogy Feed
Once a day we send a summary of activity in all the profiles in surnames you are following.
We also include a G2G Feed with questions and answers that have been tagged with the surnames or project tags you're following.
This update only goes out to those who choose to follow surnames/tags.
You can opt-out of these updates on your Settings page.