Earlier quoted context omitted.
Blocking at the DNS level produces a lot of requests to 127.0.0.1, which can be quite annoying e.g. if you are using a local webserver for development. Also if you do not have a local webserver on 127.0.0.1 the browser still will wait for answers to your request, what can be an annoying experience. Would be interesting to measure how much CPU and memory actually is wasted with many tabs waitung for elements from 127.…
DNS blocking works quite well. It's also very effective if you can set it up on your gateway so that it blocks ads/malware for all devices (PCs, phones, tablets ... even your guests will get adblocking for free!). However, while the /etc/hosts trick works I don't think it's the best way. The reason is that while parsing a plaintext file is easy and generally fast, it doesn't scale well especially when you have to tra…
Why serve a gif, why not a single byte or something? Does the browser require the data to be parseable?
Sorry, lots of questions.
http://proger.i-forge.net/The_smallest_transparent_pixel/eBQ gives info on smallest gif/png/jpeg files which might be useful.