You can deploy your own version or have a free one collaborator account with unlimited projects.
Pros
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LaTeX editor (with autocomplete) and viewer
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comments on document
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history of modifications saved
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git connection for offline editing.
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See where the other users are editing.
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with publisher templates.
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syntax checking.
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Anonymous editing (sharing a link of a public document)
Cons
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recompile is not synced between users (each user has to recompile for see the changes)
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anonymous cannot comment, only write in the document