With your method, you would have to get an email address after every word: in your own words "i would just read until the first space and append". At the first

With your method, you would have to get an email address after every word: in your own words "i would just read until the first space and append". At the first space ("bob "), you have no indication this is a valid prefix of an email address. Secondly, I don't see how bob is a high value target. Someone who knows what spam is, and knows what a spam bot is, and knows they want to obfuscate it, is probably not someone who would make a purchase if they did receive spam. I think that's one reason spam bot crawlers don't try that hard to obfuscate addresses: the recipients are of less value than those unobfuscated.