Well, there's a slight difference, in that, with FeedDemon, you see ads (albeit, small ads) on the front end when using the program. Now, I use AISEO on my blog (we use one of the similar plugins at Mashable but not AISEO), but because I compose my blog entries in Mars Edit, I'm not sure if the ads are only on the AISEO settings page or if they are also on posts. If it's just on the settings page -- well, eh, it's honestly not a huge thing to ignore. So paying $39 to simply remove that and also get higher level support doesn't necessarily add-up in terms of the value equation.

Also, actually, the pitchforks were quite strongly aimed at NewsGator, both when they went free the first time (two years ago) and non-ad supported (which pissed people who had just paid for the software off -- I was pissed as I had JUST paid $35 or whatever it was for NetNewsWire and then they went free like literally 4 days later, and I had to wait two months for a refund or something) and when they moved back to having the pay to remove ad options (and you had people mad at both ends -- the people who didn't like having to pay to remove the ads and the people who were pissed that buying the program before it went free and ad-free still meant that they had to buy it again to get rid of ads -- even if they had paid for like multi-years in the past). In my experience, people will ALWAYS bitch about any change or option to a premium model. Always.

In AISEO's case, Michael isn't doing a good job to a) clarify the payment terms (is it monthly, yearly, optional, what) or to create more perceived value above and beyond ads in the dashboard. I think if he did that, the criticisms would be fewer and the confusion would be much, much lower.

Regardless, people will always bitch about something have a free ad-supported and a non-ad free version. It's just how it is.