Perhaps the simplest option would be to use quote marks, but prefix them with the label 'Roughly:', to indicate that the quotation is not exact. Or, in the other direction, you could add an explicit disclaimer explaining that the "paraphrases" throughout your post are actually 90% copy & pasted. What would be the least clunky way to express this? Descriptions are tiresome; is there a simple name for this cross between quoting and paraphrasing? 'Paraquoting' is tempting, though I gather some already use the term specifically to denote the paraphrasing of famous "quotes". Any other suggestions?
I'm assuming, of course, that full acknowledgment is necessary here. But one may question this. For example, the aforementioned blogger can't have thought there was anything inappropriate about his unmarked quotations,* since he links to the source that would immediately expose them. And yet I still found it outrageous. Why? I guess it's because, whether he intended it or not, as a reader I was misled by his post. I had taken it to be a substantial third-party summary, expressing the blogger's understanding of the source article. But it wasn't really his voice at all. Nothing intrinsically wrong with that, of course -- selective quotation is a valuable service too -- but it would help avoid confusion to be more upfront about it. Helpful norms would ensure that readers are able to tell at a glance whose "voice" they're hearing.
* Example of source  followed by blogger's "paraphrase" :
(1) At the opposite end of the spectrum lies what I call "organic culture." The most extreme examples of this form of social organization are the Amish and the Hasidic Jews.
(2) At the opposite end of the spectrum lies what LaTulippe calls "organic culture." The most extreme examples of this type of social organization, he says, are the Amish and the Hasidic Jews.