It's not that they're annoying, though there is that. But I've learned to ignore them, for the most part.
No, what bothers me the most (at this point) is that they make it nigh impossible to browse the internet at work and still have it look like you're doing work.
I can fiddle around in Word or Notepad, or Excel even, and at a glance it could just as easily be something important that I'm doing.
But if I want to go online and still keep up a facade of productivity, it can prove difficult when a big bright ad for Viagra™ appears on-screen.
I mean, even e-mail is tricky, because my webmail frequently shows ads of inadequately-clad women looking for "friendship" in my region. (Geographic region, I presume.)
It's hard to convince someone you're working on accounting when little animated smileys are waving to you and audibly shouting. (Never thought I'd be typing that sentence.)
So I'm grateful when I come to a site where it's possible for me to avoid the glaringly obvious ads that not only try selling to me, but to anyone else within range.
For that reason alone, I will wait until I can afford to pay to upgrade my LJ account, rather than trade up to the "commercialized" version.
In the meantime, thank you LiveJournal, for not making me hide you from innocent bystanders, who needn't know just how little a workload I have some days. ';)