tl;dr: Your use cases speak into it too.<p>For example, in FF once the awesomebar has your address then with sufficient use most addresses are only 2 or 3 characters away (6 entries shown gives a space of &#62; 100,000 entries in 3 chars, way more if you include unicode addresses!). So if it's something I'm going to use often at home then I'd look at the opposition for a geek news site and choose a unique letter if possible (not s:slashdot, not d:digg, not h:hackernews, etc.). Of course if it's an Apple audience you don't need to worry about this particular effect but you get the idea. Um, where was I. Yeah, if you want me to hit your link when I'm on the road or using others computers as opposed to simply when I'm home, or if I need to <i>tell</i> the address to n00bs not just email/tweet it then don't go for the geeky "domain hack".