Two walls good, four walls bad

In my inner monologue, services like Facebook are bad because they are "walled

gardens": most of the content they offer is either not available or is only

available in a very limited to form to people who are not also users of

Facebook.

In that exact same inner monolgue, the SDF is, of course, wonderful and grand

and a shining beacon of how things on the internet should be done. However, in

some ways, SDF is its own walled garden. Yes, SDF provides web and gopher and

email hosting and these are fine and upstanding citizens of the internet. But

the content on BBOARD and COM is only accessible to people with an SDF account.

So when huge companies do this, it's evil and exclusionary and pressures people

into signing up for their services just to stay in touch with their friends, but

when obscure, small non-profits do this it's charming and contributes to a sense

of community and togetherness.

If you look very closely here, you might spot a contradiction. And as somebody

who enjoys his thoughts and opinions having at least a vague appearance of

internal consistency, this bothers me. I'm trying to figure out if my beliefs

here are genuinely inconsistent or if there's a more nuanced understanding of

walled gardens beyond "they're always bad" that means there's no problem here.

This is one train of thought in a larger ongoing rumination of mine on the

nature of SDF. Another is: why is SDF (relatively) unique? Yes, grex exists,

and so does polarhome, but really, in terms of longevity, user counts, public

awareness and internet "street cred", SDF is kind of the only game in town, and

I'm not 100% sure why. I mean, obviously unix shell acounts are not for

everybody. I understand why there are not tens of thousands of SDF-like services

thriving all around the internet. But I'm not sure I get why there aren't a

dozen or two of them. Or perhaps there are?

Does it make sense to be active on more than one service of this kind at once?

What are the options for interaction between services like this? Is that

something we would even want?