Last summer we visited Venice in August and found quite a few smaller shops and restaurants closed for the month- but the crowds were certainly there!
Is the same true of Barcelona? Will I find the city "shut down" to some degree?

August is vacation time for Spain..while the city won't shut down you will find many places closed for the month. I know lots and lots of places close in Seville for the month of August.

Thanks.
Is it significantly more than we found in Italy?
We could change plans at this point, if necessary...

Some stores and restaurants will be closed. But in the areas where you probably will be (Las Ramblas, Gothic Quarter, Eixample, etc.) where the sites and most of the hotels are, the vast majority of places will be open. You should not have a problem and you will absolutely love Barcelona! Buen viaje!

welch,
no don't change your plans...plenty will be open to enjoy..have fun!