I do not know about the capabilities/limitations of browser in Sega Dreamcast specifically; but I know of one text-only forum named
Blue Dwarf, which is available in plain-olde HTTP, which I have heard that its owner has been quite serious about making it viewable under any browser under the sun; so you might want to try.
He even has a so-called
"hall of fame" page there, which specifically collect screenshots and photographs of people successfully using various kinds of retro computing devices (gaming devices like Nintendo DSi and 3DS included) to view/use that site.
Note: That whole site is also hosted on a single-board computer in that guy's home; this fact might or might not interest you. If I remembered correctly, this guy runs like... half-dozen websites out of a single 6 Mbit/sec residential ADSL connection (1 Mbit/sec upload speed), which is really impressive.
Another website among that half-dozen is an essay site called
A Cheapskate's Guide to Computers and the Internet; which apart from being viewable on HTTP, it should be of an interest to the general populace of MelonLand as well.
P.S.
My own personal website is also viewable on HTTP, but I doubt you would find it that interesting; it is a pretty narrowly-focused site at the moment.