The four page "Nunes memo" (not necessarily by him, just convenient shorthand) and the 99 page FISA Court opinion probably share some evidence, but the 4 page memo is not "based on the FISC opinion."
Seriously, most of what is on the internet is junk. It is tough slogging to figure out what is really going on. I think the ratio of mis/disinformation to "good stuff" is probably on the order of 1,000:1 or 10,000:1
Look for base sources. Even the junk purveyors occassionally cite and link to the raw underlying data.
Which vloggers do you consider solid?