Why do people on some forums keep going on about the Lisbon Treaty?
Because there is an amazing piece of fiction circulating widely that attributes all kind of sky-is-falling shock-horror consequences to effects the Lisbon Treaty will supposedly have on the UK in the next few years, with specific mentions of the key dates of 2020 and 2022.
It doesn't bear repeating all the lies, but some of the nonsense includes the "facts" that the UK will no longer be a sovereign nation, that we'll lose our judicial system, have to join the Euro etc.
Basically it's a laundry-list of the most absurd tinfoil hat conspiracies you can possibly imagine, all blamed on the bugbear of the "Lisbon Treaty."
None of it is completely true. About 10% of it is half-true, 10% has a grain of truth of it, and the other 80% is out and out lies.
Unfortunately, as the Brexit debate has heated up, variants of the document have circulated more and more widely on social media. But you can circulate a billion texts about how the Earth is flat, and it won't suddenly turn out to be true. Similarly, just because "more people are talking about it" doesn't make any of the nonsense being shared about the Lisbon Treaty any more factual.