It may depend upon how many people are hitting the Spam button when they receive the newsletters in a GMail account. I sign up for a lot of newsletters and they all go to a GMail account. While most site owners send a periodic newsletter containing what they say they will send, others do border on spam because I get deluged with advertisements, scammy misrepresented promotions and things that I didn't expect. The worst ones are the newsletters who do not take your e-mail off of their list when you request it.
Lockergnome is mentioned in the article. Up until 5 or 6 years ago that newsletter contained useful information. For the past several years they went on a binge to build content and started sending out a lot of garbage. The Lockergnome web site itself contains most of the garbage articles, so it may in reality be the web sites themselves that are the problem and not the newsletters. The author of the article assumes that his articles are not part of the problem, but that might not be the case. I checked his web site and the articles look okay, so my jury is still out on this one.
One of the things that I noticed with Panda is that sites with rambling blog postings and lots of unrelated content appear to have been hit. Keep your content unique and focused on a theme and you may never see a problem. The traffic is up considerably on my blogs that focus on a topic.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin