A little while ago, Google introduced the ability to automatically delete some of the data that it knows about you.

While that seems like Google turning over a new more privacy-focused leaf, it might not be quite as meaningful as it first appeared.

The setting, which you can find on Google’s Activity Controls Page, allows you to automatically delete certain data after three or 18 months. While this automatic deletion is great to have, the time frames did seem a bit odd.

After all, three months is a relatively long time to be the shortest time frame.

And it turns out that more recent information is much more valuable to Google (and people targeting you for ads), so information that is more than a month old is basically worthless. Both to Google and to other advertisers.

In an article over on Fast Company, David Dwek, explains:

[I]n the digital ad industry, recent activity is essential. If you start searching on Google for real estate or looking up housing values, for instance, Google might lump you into a “prospective home buyers” category for advertisers. That information becomes instantly valuable to realtors, appraisers, and lenders for ad targeting, and it could remain valuable for a while as other companies, such as painters or appliance brands, try to follow up on your home buying.

This kind of information has an expiration date, though, and it’s probably shorter than the 3-month auto-delete setting that Google gives you.

If you really want to keep Google from targeting you, you’ll need to delete the information manually. To do that, you’ll have to delete it individually from three different places: web and search, YouTube, and location history.

If Google starts offering a one-week or 24-hour deletion option, that would be very interesting (and potentially very expensive for Google’s core advertising business.