Tenuous, Anonymous is just a mask to get yourself media attention where Knights had organisation and skill. The only similarity I see is that people who associate with both groups use technology in attempt for social change.
http://ghostintheshell.wikia.com/wiki/Laughing_Man
"'The Laughing Man' became something of a pop culture obsession for a time, much to the chagrin of the actual Laughing Man—the irony being that since everybody used his icon and name for their own purposes, the original meaning of his actions, an artful forced confession of the truth through fear in the public eye, became 'phony' itself. The effort to stand for and demand the truth was also lost forever."
That's so similar to how I at least understand Anonymous to exist that it's sends some chills up my spine. The things done in the name of Anonymous are all practically verbatim "Stand Alone Complex" type scenarios where there's not really a leader driving anything, but the interplay of "The Media", individual goals and interests, and a pseudonym to take credit all work towards the creation of a self-sustaining identity utterly independent to the original inspiration.
Meaning that people employ variations of Anon tactics, as reported by the media, against people and groups for the flimsiest of reasons.
Now we have trolling, sock puppetry, link echo chambers, and other mechanisms that attack our tendencies of contributing in social networks that make it easy for even a single individual with nothing but disdain and time to derail or discredit if sufficiently motivated.
It isn't Anonymous, but the penetration of internet and social network into everyday life that makes these tactics more effective than ever, and so anyone with a spare five minutes and a chip on their shoulder can froth the waters; they don't have to be living in their mothers' basement and have a file called "my_hidden_agenda.txt" on their Desktop.
Someone who knows more history than I do can probably take them a lot further back to (e.g.) public pamphlet debates in the 17th century. I wouldn't be surprised if there were Roman and Greek equivalents.
Anonymous independent-action-under-a-common-pseudonym has a long history in politics. The Angry Brigade and King Mob are two recent pre-Internet examples - from the UK in the 60s/70s.
Historically, Internet trolling is a lot more civilised than some of the things that used to go in previous centuries. Trolls may be rude to you on Twitter, and they may even dox you and cyber-stalk you. But unpopular people don't often have to face a lynch mob or a riot outside their front door.
Why would you say there has been an upsurge in trolling recently?
I'm not disagreeing per se, but the amount (and type) of trolling you see on your daily web browse is one of those things that heavily depends on the particular filter bubble you live in.
If you were to ask me, personally I observe way less trolling than back in the day, but I wouldn't call that a general trend cause I know it's just the part of the web I see.
There's one thing maybe (but again it might just be a function of the things I like to look at), is that a whole bunch of different trolling techniques that would have been considered "creative" or "highly original", most of them related to culture-jamming/subversion (in a very broad sense), memetics, or absurdism/surrealism, are not quite as "special" any more and routinely employed by (young) people for fun on media like Tumblr, etc.