In HTML a million spaces in the source is exactly the same in so far as the final page as if there were only one space there. The only difference is that the more spaces in the file the longer the file will take to download. Now a few extra spaces isn’t going to make a noticeable difference to the download speed unless your visitor is on a really slow connection. Some web pages may contain thousands of extra spaces beyond what is really needed though and that may be enough to make the difference for some of your visitors between waiting for the page to finish loading and leaving before it finishes. The other area where these spaces can make a difference is if your web hosting has a limited bandwidth or where you pay based on what you use. If a million visitors view a page where you have managed to remove just one space from the file then you have saved yourself 1Mb of bandwidth.