The new birth index has already filled in quite a few gaps in my family tree, where I'd guessed there might have been other children but didn't know for sure. Even though I knew how high infant mortality was in the nineteenth century, it is still sad to find so many little ones who didn't make it.
I hope it will help put some little lost Olivers in their rightful place in the family tree too.
In case anyone hasn't discovered this already, the General Register Office has put some new indexes to English & Welsh birth and death registrations online. These cover 1837-1915 for births and 1837-1957 for deaths.
The birth index is a major new tool for genealogists because mother's maiden name is included for most entries (until now, the national GRO indexes, based on the old hand-written ledgers, only started including mother's maiden name in 1911). That makes it possible to identify relevant entries much more easily than via the older indexes on FreeBMD, Ancestry, etc.
Annoyingly you can only search a few years at a time, and have to specify whether you're looking for a male or female. It's worth the effort, though. It has helped me fill in some gaps in the family tree for children who were born and died in between censuses. I've already found two more children of my great-grandfather to add to the 18 I already knew about.
The death index is also improved, as ages at death have been added to many of the earlier entries.
One frustration is that you have to log in to be able to use the indexes. If you've used the GRO site to order BMD certificates in the past they should have e-mailed you with an activation code. If you've changed your e-mail address (as I have done) you'll need to re-register. You can register or log in here. Once you've logged in, a new menu appears, giving access to the search form.