This is a bug that I reported on GNOME's epiphany-webkit 2.27 (packaged by Kov against webkit 1.1.1) and found its memory usage to be pretty dramatic. The Midori browser (which also uses webkit) has the same pattern. I thought I'd report it here so it can get some attention from upstream. I presumed if two webkit browsers have the same behavior regarding memory usage, webkit may have something to do with it. "Demonstration of the problem: http://jeff.ecchi.ca/public/epiphany%20webkit%20memory%20usage.ogv I need to kill epiphany twice a day to go back to a sane level (and stop swapping for nothing). Just now, Epiphany was using 473.9 Mib of ram (according to gnome-system-monitor's "memory" column), and after killing it, restarting it and waiting for all tabs to load, it is now using 187.6 Mib. That's quite a significant difference that cannot be attributed to caching webpages in memory, and it makes epiphany painful to use on machines with less than 16 Exabytes of ram. For what it's worth, Chromium doesn't do this (but then everything is a separate process over there)."
for my part i've noticed that GtkLauncher didn't free up the memory if i visit several websites and go back to the inital website
Lots of things can affect memory usage including cache size and memory leaks. WebKit2 will eventually ensure that Epiphany has an architecture similar to Chromium's.