[prawn]

Something like that but without the barrier/limit that stops people from continuing to browse the site.

With Tinypass: hits limit of 10 articles, donation of $5 requested; non-payers go elsewhere for their content

With my hypothetical: user ignores donation at 10 articles, maybe gets to 100. Isn't going to a competitor for content. Potentially decides that 100 articles seems like a lot, surely that's worth at least $5.