>>39
the gui is very easy.
http is just a protocol. a compact and efficient implementation is possible. Caching could just be a hashmap from "domain-name/path/to/file" to the spawned structure that was created from the fetched data. Elements not recently used could be saved to a file, or destroyed, to save space.
html is easy to parse. You can always ignore tags that you don't understand (although hopefully enough of the main ones are supported).
CSS isn't that difficult to parse. It looks like the entire language is outlined below:
http://www.w3.org/TR/CSS/
Once the html renderer can support the styles in CSS, it wouldn't be difficult to tie all that together.
Forms are just textual boxes. All of these things may take programming effort, but there is no reason for it to consume lots of memory.
The amount of memory used will be proportional to the size of the web page, there is no getting around that. So if the running javascript tries to allocate an array of length 6000000, then I'm kind of screwed. Although memory resources used by scripts should be capped anyway to prevent malicious pages from crashing your browser.
>>40
Not all devices have a Gig of ram. Even if it's cheap, it might not fit.