Walkers were randomly dying on some specific feeds. After wandering around with things for a bit, I noticed that the HTML for those feeds had some really, really stupid nested tags — hundreds and hundreds of nested <font> tags, for example. Anyway, it turns out that PHP isn’t very good at recursion and when a website hit somewhere around 500 layers of nested HTML tags, PHP threw in the towel on behalf of my html-simplification routines.

It’s becoming clearer and clearer: PHP is simply not a suitable choice for creating stable back-end processes.