If a site is developed ostensibly for one purpose, but the monetization strategy is skewed in favour of some other purpose... what do you think is going to happen to the site over time? Whose interests are going to be prioritised?
Sure, the intentions are good, and you'll try your hardest to serve all your end-users, but if you have an actual, paying subscriber demanding a particular feature (or they'll take their money and leave) vs a feature that the non-paying community has been asking for... which one is more likely to make the cut?
Who is the real user here? Well - the sponsors...
I'd actually have paid to get a better service than this - to get them to finally (after three years) allow me to get graphs in the metric system or to not see the advertising. But the CEO is convinced that he's being generous by keeping the site ostensibly "free"... unfortunately - the site clearly isn't free. It's paid-for by customer attention.
But how did it get this way? I mean the owner is clearly a fanatic about trying to help people to lose weight, willing even to spend a very large amount of his own personal fortune to set up and maintain this site. So why did these anti-features appear in the first place?
It's simple common human nature that's to blame.
If the motive for a site does not align with the motive behind the money-flow, then you'll have two masters to try to serve - and it's obvious which one will win out. It's a much better idea to find a way to align these two.
A good example of alignment is in White Label Dating (a company I used to work for).
They are a company that allows people to set up their own, branded dating sites. For example, a women's magazine might decide they want a dating site. Rather than building one from scratch - with the near insurmountable chicken-and-egg problem (not to mention a strongly gender-skewed audience), they can come to WLD and quickly build a site that has all the functionality ready-made... along with access to a *huge* pre-existing database of daters... but also allows them to put their own branding on top. It's a "white label" dating site.
Now WLD's monetisation strategy is as awesome as it is simple: they revenue share. That means that for any individual dater that pays for a membership through the magazine's site - a percentage of the money goes to the magazine, and a percentage goes to WLD. The magazine is incentivised to use their brand and existing audience to promote the site -> getting more memberships, which gives them more money. But better yet, WLD are incentivised to make a good service for the end customers (the individual daters) because that way people will be satisfied by the service and continue with their membership.
The end result is a system that works for WLD, works for the magazine... but *also* works for the individual daters that sign up for the service.
That's how it should be.