I would say that less news would get out to the right wing. Blogs inform the right wing, but if they weren't there, older methods would be used. Blogs do not expand the number of conservatives, and as far as I can tell, they don't make conservatives much more active. They're a bit more than a toy, but are more accurately described as a toy than a major weapon for conservatives.
As for Hillary's interest in shutting down conservative blogs -- if that's the case, there are two explanations. One, many socialists are totalitarians, hating anything that is outside their control. In short, control freaks.
Two, people like Hillary fear that blogs could become significant. I'm not saying they can't, but I haven't seen it and don't foresee it in the short term at least.