I made the mistake of providing my date of birth as being 1/1/1900 on multiple websites, and have been receiving marketing material from the AARP in the mail for many years.
If I ever turn uBO off, the ads I get are mostly for funeral plans or incontinence products, with a smattering of "126 year old mom lost 30 lbs of belly fat - click to see how!" (yeah, decomposition's a bitch...)
And, for the record, it's way better to get ads for BS like that than stuff that may actually influence you.
Don't limit, notify.
Has worked for TV (and movies to an extent, though theaters do limit somewhat, must have been some litigation around that...) pretty much forever.