Blogs certainly can be slashdotted, and they get looked at a lot more when that happens. A big difference between a blog and a regular periodical, whether clipping service, journal, or magazine, is that blogs don't have to be published regularly. Many of them are mostly daily, but if the author is away from the net, hasn't found anything interesting, or just doesn't feel like it, there's no obligation to post anything on any given day. Of course, science fiction fanzines are also often irregular. Bloggers often read each other's blogs, making blogs the basis for a geographically distributed literary community, much like fandom, except with faster interactions.
Many people wonder how blog authors find the time.
Larry Wall invented the greatest labor-saving device since sliced bread. I use a Perl script that extracts URLs from mail and formats them for the blog. I look at them in an editor, reword a bit, and then let another Perl script slap the new URLs into place in an HTML include file. Most of my blog entries come from assorted mailing lists that I read quickly during the day, including not only work-related lists but also the list that dare not speak its name, the one with rotons and the flaming O, several with the flaming P, and the one that can't discuss ice cream sandwiches. I often don't have time to peruse the links while skimming the lists, so I file them in the blog for later perusal.