I am utterly subjective on that matter. And sometimes even biased. Nonetheless, you won't find crappy Beepworld pages here, added for the reason that my sisters unborn baby has rustled up a page on hamsters. The pages are far from brand-new upcoming pages. I tend to look at a page for at least six months, before I decide, whether I link it or not. There are tens of thousands of blogs out there, which link new, upcoming pages. Read the "Info" for a general idea why I have chosen that particular page.
Sometimes links also get deleted, but this is mostly due to the pages disappearing, people asking me to take their links off, a dramatic decline on the page quality, or the page not being updated for ages.
But the general rule is: When I go "Wow", chances are high, that I'll link it :o)